Glad you weathered your first camping trip without any major catastrostophes! Any reason you didn't try showering in your rig? For a weekend you should have had plenty of holding tank capacity, especially with your black tank. Gotta use all the systems to make sure they're working.
About your hitch ... It might need some adjustments. There should be heavy rubber washers on the receiver that can be added/taken off if necessary. I had the very same thing happen with a trailer once & after getting it home the RV guy adjusted it & it never gave me any more trouble. Just because it's a new setup shouldn't make it hard to disconnect. If your RV dealer is nearby I'd hitch 'er up & take it over. Let THEM see if they can get it off easily. If they can't they should be able to help you. They should have checked it before you left anyway ...
We'll look forward to hearing your future adventures. You've got a beautiful trailer and a great tow vehicle -- you'll be able to go anywhere you want!
Laura