I haunt the 3 big RV'ing forums and have for the last 18 years and I've read a few times about people being told to toss their AC and then them doing a DIY deal where they add saddle valves, then add leak detector, evacuate and store the Freon if required, fix the leak or replace a compressor, then charge it up and off they go.
Of course I don't ever recall hearing back that it worked. These were HVAC techs or they hired a friend who was. Usually they'll pull the AC off the roof and have it set up on sawhorses or a picnic table, plugged in ready to test.
Myself, if I were needing to do that, if I determined it was a slow leak (weak cooling, not completely stopped), I'd add the saddle valve than use Enviro-Safe
coolant. Bigger molecules so not likely to leak around the saddle valve. Likely to get several more years that way. I'm using it in the dash air for my DP and it's working good so far.
In your case, you should maybe buy a set of Start/Run capacitors. Might be that one is bad and the compressor can't start. Could be as simple as that. Or it could be a broken or loose wire to the compressor.
Really might be better to help yourself out if you could arrange to have it removed and setup next to your RV. Gives you many more easy to accomplish options, plus easier to determine if it can be repaired and you're ready to install a new one as well if that's the decision. Maybe the RV park has a forklift? Or a scissor lifter? If it's removed, a cardboard cover taped in the hole would work unless it's raining all the time. Then I'd opt for a piece of 3/4" plywood inside a plastic garbage bag, and a couple screws to hold it in place.