SUSPICION IS YOU WILL NOT FIND ANY FULL SETS, you (Might?) find partials/ systems, but do you have specific problems? Otherwise, you search for/by CHASSIS Ford, MB, (99-e-450sd) etc. and/or Coach Systems, e.g. Water Pump, Furnace, Water HEATER, by BRAND/ MODEL ##. I.e. FLoorplan dictates Appliance Location and Most (appliances) need either 12vdc or 120vac or both handy, regardless of Brand/ Model. Further, if floor (say around toilet) or closet/wardrobe have funny angles, it is because a bundle of wires or water lines or both go thru it. Hope this helps. Not too hard, once you think about it. Receptacle Here, here and here, Power Source there, how would YOU route the wires? and chassis wires, Most chassis wiring UNDER chassis buried in plastic corrugated sheathing that all looks alike ...UNTIL YOU OPEN THE SHEATH TO LOOK AT WIRE COLORS
THOSE build diagrams easier to find
Luck to ya.