Friday, December 9, 2022


RV review: 2021 Keystone Cougar 357UMR Fifth Wheel


By Tony Barthel
A lot of interesting things have come out of the past year where so many of us got our plans altered. The folks at Keystone also found things changing in the past year and one of the results of the shift of some customers’ preferences was a new floor plan for Keystone’s Cougar brand. The Keystone Cougar 357UMR is the result of listening to what some customers were asking of the brand when it came to the floor plans. 

Some of the model designations for RVs are pretty obvious, but “UMR” might throw you until you are told that it stands for “Ultimate Mud Room.” Yep, Keystone built an RV kind of like your grannie’s beach house. But cooler. 

The Keystone Cougar 357UMR is a larger fifth wheel from the brand that features all the things you might expect from Cougar, but with the twist of having that mud room. It is located in the back of the trailer and, like grannie’s mud room at the beach cottage, it has its own entrance. That means you can clean up before you come into the actual living quarters. 

In fact some of the customers mentioned by Keystone in their video are the folks who are working in the oil fields. But there are plenty of others who might appreciate this floor plan, as well. 

What’s inside the Keystone Cougar 357UMR

There are two doors to get into the Keystone Cougar 357UMR, one at the very back and the other where you’d expect it in a larger fifth wheel, at the center. Assuming our feet are clean, if we go through the middle door we end up right in the main living area at the base of the stairs leading up to the bedroom. 

Since I know you’re all interested in the mud room aspect of this, I’m going to save that for the end. Upstairs there’s a bathroom, as you’d expect in a fifth wheel, complete with a seat in the shower and a decent amount of space there. Further down the hall is the bedroom. This comes standard with a queen-sized bed, but Keystone says more folks opt for the king-sized bed. But at least you have a choice. 

Across from the bed is a dresser, and then the nose is all closet space with a set of cabinets on the camp side. Nothing remarkable up here, but it is a decent layout. 

The main living space

The main living space in the Keystone Cougar 357UMR has a couch on the forward wall which is a tri-fold sleeper sofa. Around the bend from that are theater seats. These have heat and massage as well as USB charging ports in the cup holders and a bit of storage in the arm rest. 

Next up is a choice of either a booth dinette or free-standing table and chairs. Keystone has made some nice changes to the free-standing table and chairs. Those include mounting the table directly to the wall so there’s no knee knocking pole coming down for support of the table. As someone who displaces a lot of water in the pool, I also appreciate that the table slides back and forth. So the idea for someone built like me is to sit across from someone built like a kid. 

Another choice to make is directly across the floor from the dinette table – in the refrigerator department. You’ll have to choose either a traditional gas-electric RV refrigerator with 12 cubic feet of space, or a larger 16-cubic-foot all-electric refrigerator. 

The all-electric fridge is a residential model. Keystone very specifically mentioned being able to run it off the inverter as you’re rolling down the street. Further down the space is a three-burner Furrion stove with a 22-inch oven. Then is the huge 50-inch TV atop a space heating fireplace that can throw 5,000BTU of heat. Of course, there’s also a furnace. But the fireplace is nice for both ambiance and also for heating the space on the electricity you paid for when you got your site in a campground. 

In the middle of it all is an island with a lot of drawers and cabinet space. 

Now … the mud room in the Keystone Cougar 357UMR

How many of you have skipped ahead to this part? That’s what I would have done, too. As mentioned, the mud room in the Keystone Cougar 357UMR has its own entrance, which makes it really useful. 

Along the back wall there’s a huge utility shower that Keystone says is pet-friendly. Depends on the pet, and I know some of you travel with cats. In that shower is something I haven’t seen in a while. That’s one of those clothes lines that extends from sort of a “disc” on the wall with a receiving latch on the opposite wall. Makes sense, since you can hang your swim suits or towels on the line and let them drip into the shower. 

There’s a closet on the road side rear of the room that has adjustable shelves and a cabinet overhead. But the closet is also plumbed for a stacking washer-dryer – which is also like the mud rooms I remember as a kid. 

What’s not like those mud rooms is the desk that’s back here, although my grandmother would have used that for the sewing machine. Nowadays you might make “sew sew” comments on the internet, but not as many people sew. You have no idea how happy I am that I worked those terrible puns into that paragraph. 

Lastly, there’s a large pantry on the camp side of the room. 

In summary

As I write more and more of these reviews, I see some companies where there is an ever-clearer distinction that they’re spending time making a difference. Keystone is one of those. 

For example, the company has spent a bunch of engineering time looking at air conditioning in RVs. It has developed a 360° air conditioning duct that they claim leaves users with fewer hot spots in the rig and also delivers up to 20% more cold air. On the subject of cold air, the company has also tested their trailers from 0-110° F in a test chamber to make sure occupants stay comfortable at those extremes. 

I also have particular interest in the company’s HyperDeck™ flooring, as the flooring in my own RV has begun to fail. So improved waterproof flooring is a key distinction for me. Also, I also had to manage warranty claims where our techs spent literally hours trying to decipher the wiring in RVs. So the fact that Keystone uniformly color codes their wires is another big plus. 

Kudos to Keystone on good product information on its website

Lastly, here’s something of interest that might just be my own passion, but Keystone really does disseminate useful and thorough information on their products. The advantages I just wrote about and really nicely done walk-through videos among other things are not some mysterious formula. But they are rare in the RV business. So I want to hand it to Keystone for having good information about their products on their website. 

Well, there is one exception to that. This is such a new model the company hasn’t formalized tank sizes or a few other things, so you’ll notice that today’s story does not come with a specifications chart. I’m sure the information will be available shortly, but it isn’t at the moment.


These RV reviews are written based on information provided by the manufacturers along with our writer’s own research. We receive no money or other financial benefits from these reviews. They are intended only as a brief overview of the vehicle, not a comprehensive critique, which would require a thorough inspection and/or test drive.

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David F.
1 year ago

Just curious, what do you think the pin weight will be? Under or over 3000lbs.?

1 year ago

The mud room is very cool! It’s own entrance, the huge pet shower, plumbing for washer/dryer, pantry, and a DESK?!?! I am a big fan! What a clever, unique idea!

Sink Jaxon
1 year ago

No matter how you view this floor plan, rather good or rather bad, it won’t matter when the quality of Keystone products is JUNK. I mean, shoddy workmanship, no fit and finish and overall bad construction ready for the junkyard when fresh off the line. I know, I bought a Cougar in 2017. The roof membrane bubbled up and nearly tore off, the slide-out broke in the open position the kitchen faucet leaked at the connection and swelled up the counter top, window cranks stripped out, I could go on and on with the problems but add insult to injury, Keystone ignored me and did nothing about it. Buyer beware! DO NOT BUY A KEYSTONE PRODUCT! This comment is based on my personal experience and opinion, use due diligence and read all the reviews you can on this JUNK RV and you’ll agree. Note: This comment is not intended to criticize the author of this review.

1 year ago

No dimensions, GVWR, CC, MSRP? And are the queen and king beds “standard-” or “RV-” length? What are we paying you for, Tony? Just kidding!

Who expected a mud room in an RV? Forget pets, it would be great for two families with four-wheelers or motocross bikes. One with a big toy hauler and the other with a mud room to clean up enough to be allowed at the dinner table. After your shower, you just throw the filthy clothes in the handy washer-dryer and have them ready to get dirty again the next day.

1 year ago

The mud room is pretty cool. The only thing I don’t like is having the dinette and recliners on the driver’s side. Why have to look at the neighbor’s campsite when you could face your own? Just don’t understand it.