I have a 2008 1500 Ram which I wired to tow. Yes, you will need diodes for the circuits you plan on using. I don't know why you would need any sort of converter since you will be using the 12 VDC off the coach. Good luck with your project.
Bob Retired Army Traveling alone now, had to put Charlie the Beagle down :(.
2008 Camelot 40 PDQ 4 slides ISL400 towing a 2020 1500 GMC Sierra Denali 4x4 Crewcab
Western MT in summer, AZ, NV in winter