Excellent ideas here. Common sense will be your most valuable tool and keeping up with the posts here from the sharper fellows. My $0.02:
1.) If your MH has air brakes, obviously you have an compressor unless your engine is dead. Make sure you or the dealer installs an air outlet quick-connection.
2.) Good quality cordless drills also have available good quality work lights, I have a Dewalt fluorescent. A good quality light can be invaluable.
3.) I am not a big fan of the large tool boxes with drawers even though I have one, my favourite method mentioned above are the canvass (Klein) or synthetic fabric tool bags (Craftsman) of various sizes, I have three of those. Klein also has the smaller canvas pouches I use for the smaller stuff. The fishing tackle boxes are a good idea if you have the space.
4.) Various size zip ties.
Good luck, Mark