People have done this sort of thing. It's a lot of work, but it's not impossible for a handy do-it-yourselfer. If you're hiring someone to do it the labor will make it fairly expensive.
Not infrequently the floor also needs attention as water collects there. If you have wood framing in your trailer, it may well be rotted and require parts to be replaced. (If you have aluminum framing, that's obviously not really a concern.) Expect the project to take longer than you think, if only because the access and working conditions in an RV are rather cramped and tight and there's generally a good bit of finicky fitting etc. to do.