Probably not your style with the description you gave but this is a nice one...

https://www.byangelaprice.com/blog/2020/8/11/rv-the-big-interior-reveal

You can look on Amazon for pillow covers and pillows. Southwestern style, leather/ faux leather, velvet - whatever you like.

I don't believe how white cabinets, etc. are even showing up in some campers these days! It used to be all wood! You could bring in a large wood cutting board or two and some other wood accessories in kitchen area.

Here are a few images I put together with AI.

You could use fewer patterned pillows if you prefer, these are just some general inspiration pics. :)

Of course storage will be at a premium, so I would think of functional pieces. I think a Navaho style throw/blanket across the back of the sofa, and a wood or leather piece for on top of the refrigerator that can organize for you, slide in a drawer for travel, but could also move onto your table when you're parked. Maybe a graniteware coffee pot?

I tell clients:

I don't do garages. I loathe basements and I definitely don't do camper vans.......but you have helpful ideas above : ) : )!

As you can see, everyone is far more helpful....than MOI!

Did I mention my idea of "camping" is the Ritz Carlton in Laguna Beach?!

Any wool furnishings should be easily removed for cleaning to prevent moth and carpet beetle infestations. Some wool items are machine washable in Woolite, hang to dry, so they are far easier to take care of than those that have to be dry cleaned. Colorful vintage wool Pendleton or more affordable Faribo blankets are available on etsy and eBay. For example:

https://www.etsy.com/market/faribo_wool_blanket

AI came up with this...

"Manly decor usually means no ruffles,no drapes,no lace.Be careful about wool blankets...fringe ok but you want washable fabrics.
The "navaho" theme is a trifle trite.Try a lumberjack,western theme with leather,checks ,plaids and coordinating deeper colors.
Nice if you can get comfortable indoor/outdoor easy to clean cushions and seat covers.Maybe incorporate art that vibes positive...no hunting/ prey / weapons pics if you intend to entertain opposite sex? Keep doodads to a minimum...they bounce around and make extra dusting.Love Jan Moyers take on camping...my idea of camping is "room service".

In my experience, AI responds to word prompts. So the results are related to the word prompts that are used . Maybe the visual directly above was created with Chat-GPT; I have not used that platform, so don’t know the capabilities - but I am assuming that it does respond to word prompts.

Anyway, as you see, there are many ways that you can go with your decor, accessories, etc.

Here are a few more AI visuals. I included some Pendleton blankets in these, as were suggested by @la_la Girl upthread. Also, notice the pillow mixes. Plus, a few wood accents here, too.

So much fun. I love the idea of mobile living.

Btw, ignore the rude comments from the clueless/mannerless/pretentious... Why someone shows up here to announce that they don’t decorate campers (when this is clearly a post about an RV/camper) is beyond me. Really... who cares where they stay when they are in CA ( or anywhere). Just a heads up: you can flag inappropriate comments and/or send an email to help @Houzz .

Have fun with your project!

I think I'd add some red and orange tones. Since you need to store the bedding, I'd focus on elements that do double-duty. The seating looks awkward. What's going on with the cushions in the back?

Telling people what you do not give advice on has validity.It helps the questioner to reflect and focus on what is really relevant to them.
Remember,whole dimensions lie glistening on the dark side of even the most dull and commonplace thought.We all have some kind of preferences and favorite themes,and it is a mark of intellectual honesty to at least even if briefly to entertain possibilities we usually dismiss.Houzz design dilemma is so highly popular that frequent contributors cannot totally decline to chime in!

I would change out the tabletop to solid real wood that is varnished with Varathane to waterproof it. Something with a nice grain or even butcherblock.

Get some slipcovers for the cushions, the vinyl does not look comfortable. I'm thinking a heavy tweed fabric with gray and brown and tan flecks in it to tie into the other colors. Something washable and with a nice feel.

You could buy fabric by the yard and attach it to the back of the cushions with Velcro for an easy DIY and there must be a something on YouTube. Basically wrap it like a package.

Highly suggest not going with a western/southern feel due the interior’s contemporary injections: cabinetry finishes, counters, flooring, table top. Also in this small space I think it‘s important to feel calm and relaxing; therefore, I really like your idea of natural/warm elements, additions of leather, wool, wood, and (suggest subtle) patterns. The ideas below feel masculine and even better, I think suit your space.