I fixed the compatibility problems between this and Bernd's camper. I also added an extended range fuel tank, messed around with a bunch of Jbeam stuff, customized the drivetrain and suspension for the config, and I think there was something else (I can't remember). Don't worry, I'm not done with the skin. The hood and front/rear panels aren't going to remain white.
The sound is total possible. I don't know that it will be bundled with this project, but I can make a small separate mod for you that does what you're asking.
Eventually. It's in the planned features list on the first post. --- Post updated --- Here you go. Just put it in the mods folder like you would any other mod.
About this many so far (the walls fall off too). It's very similar to the Travel Trailer in that every piece of major furniture has a separate Jbeam. Longer? -> Yes Shorter? -> I wasn't planning on it. The RV is fairly short already. It's only 24ft from bumper to bumper.
More progress on the skin: I should look into why the awning turned black. I didn't authorize it to do so.