How can I make a headboard for the curved wall in my Travel Trailer

How about getting a large piece of foam? It will bend to fit the curved wall. Cut it to size and cover it with fabric to match your bedding.

Here are a few ideas on hometalk. Check through them and see if any will work.

http://www.hometalk.com/search/posts?filter=light%20weight%20headboard

How about a piece of upholstered 2-3" foam, fit to wall and put some moulding to hold in place. You could use vinyl to cover for easy clean.

Be sure to show us how it turns out!

I just did this to our fireplace and it was free. Home Depot had unpacked some big appliance and they let me take the styrofoam. I shaped it to the fireplace opening and covered it with a silk scarf taped into place, gorgeous, plus you can trade out when you like. You can do this for a headboard, so easy.

You know wiggle board might work here. Wiggle Board or bending plywood is designed to flex to take the shape of almost any curved contour. Bending plywood’s ability to bend in long-grain or cross-grain directions makes it a versatile panel for complex shaped designs.

Hi Judy, hope this helps you. Why not do peel and stick wallpaper?

https://www.amazon.ca/s?k=peel+and+stick+wallpaper&crid=GZ5KVUO7UQMS&sprefix=peel+and+stick+wallpaper%2Caps%2C167&ref=nb_sb_noss_1