As far as the "coach" , you'll find that almost all the "fittings" are screws, and if any small nuts, are usually sae.
Take a look around your interior and you will find almost everything is attached with screws, usually, but not always #2 square drive. Most others are phillips head. Any self tapping hex head screws are usually 1/4, 5/16 , 3/8 inch drive, which can be taken off by a nut driver.
The appliances are usually just held in place with screws.
I carry an assortment of wrenches, sockets, ect, for the larger stuff on the chassies or cab (ours is a class c) and most of the Ford based fasteners are metric.
My most used hand tools dealing with the interior are a small power screwdriver, a good set of regular screw drivers, and several #2 square bits.
Very few "nuts n bolts" used on the interior. Several I have found, like ones holding couch to floor, slideout hardware, ect, are sae.
Steve & Cheryl + Zoey, and Ziggy, our furry kids.
2012 Forrest River Lexington 283ts
Toad, 2013 Subaru XV Crosstrek