So, assuming you have a 50 amp coach and you have the adapter (dog bone) that takes the 50 amp down to a 30 amp and the adapter that takes that 30 amp plug down to a 15/20 amp plug then you can ignore all the previous posts about having power to only 1 leg. Every plug and electrical device in your coach will be live.
That, of course, is also the problem. You need to ensure that you turn off everything you don't need and set your battery charger (inverter/charger?) to a 15 amp setting to ensure your batteries are getting charged. If they are badly discharged this setting may not give you a very good charge but if the batteries were fully charged when you parked your charger will be able to maintain them just fine with this setting.
Be sure the fridge is off or running on propane and be sure the same is true if you have an electric option for your water heater.
A few things can actually be run but you will likely have to ensure you only use 1 appliance at a time. This applies to the A/C as well in most cases but you want to be absolutely sure there are no other draws.