same as snowdance here. If parking is temp so as to have a lunch or some short time visiting a museaum or such than just leave it be. I placed levels on the outside of the fridge door for longitudinal level and one on the sidewall for lateral. I leveled the coach and took reading with bubble in center of bottom of fridge, confirmed in the freezer than placed the 2 levels indicating the level attitude. Now pull in and wife can look and tell me where we are at. Also have on the TT one above the hitch and one on forward side of sidewall to check while I level with the jacks or add blocks as may be required.
I also travel with the fridge on, both in slide in camper and TT. No issues.
Parking on your slope with everything off is no problem, but I would just level it some to make entry/exit much easier while parked. Only thing the non-level will do is afford good drain off roof when it rains.