How can I decorate the inside of an RV with a rustic decor?

Perhaps you can get some ideas from this post. https://mountainmodernlife.com/rustic-camper-remodels/

For inspiration with rustic decorating ideas, I would suggest that you go to website of Colin and Justin. They are two Scottish Canadian interior designers who specialize in rustic/cottage/cabin/lodge decor.

. https://www.colinandjustin.tv

https://www.cityline.tv/video/4-jaw-dropping-rustic-home-transformations-by-colin-justin/

So collect rustic decor as you acquire it. Doesn't have to be purchased or DIY'd all at once. Just like accessorizing your home, bits at a time.

I am in the process of fixing up one of my male clients RV in a rustic style. I got some large buffalo check comforters for the beds. I'm making moose curtains.

I am making the bathroom more accessible by putting in a barn door for a larger opening. And I plan to make it a wet room after installing a floor drain.

We will be ripping out the rug, and putting in luxury vinyl plank in wood tone. I may also put the thin wood plank on the ceiling.