It sounds to me l like you've blown a relay (or two). it may even be the main Accessory Relay which controls many of the items you've mentioned that come on when you turn the key. The Relays should be located somewhere on or near the main chassis fuse block. Could be located somewhere in the engine compartment. You can Google "how to test a relay" if you're not sure. Did the RV not come with a Cummins manual? To find the correct manual for your 5.9 Cummins RV chassis, you must locate your engine's dataplate (a metal tag on the engine) and use its Engine Serial Number (ESN) to look up the specific engine model and its manual at http://www.cummins.com/support/manuals. I would suggest that this is a Cummins chassis issue, not a Forest River issue. You may have more luck reaching out to Cummins for help?
