If this is a major park, ask the management if they can offer any basic assistance. If you have made even a passing acquaintance with any of your neighbors, ask them too.
Sometimes it is as simple as the connections at the battery posts looking clean and tight but they are NOT.
EVERY RV OWNER NEEDS TO CARRY A MULTI-METER WITH THEM.
$10 or less at WalMart or Harbor Freight.
In addition, I have a portable 110 V and 12 V meter plugged in all the time too so I can see at a glance that things are still working. Those also are about $10.