Unless you just money burning a hole in your pocket - from your description I would think the problem with your AC unit would provide for a simple inexpensive fix - and something very common to MoHo rooftop unit’s whether built today, 2006, or 1990.
And it’s wiring connections, followed by wire connections, followed by possibly a failed PTC and/or failing compressor run capacitor.
Not to forget a dirty condenser, fan motor lubrication, and lastly - low voltage to the unit due to (again) wiring connections in the breaker panel of the coach, the shore power tether, or due to an again electrical system where you are getting your power from.
Just some food for thought. If low voltage is your issue, a new unit or units will probably limit your satisfaction of the hard earned money you spent.
‘91 Ultrastar Champion‘02 Georgie Boy Landau 8.1l Workhorse
‘03 Jeep Wrangler TJ 2018 Jeep Wrangler JK toad