My first trip was a long one- Whidbey (North of Seattle) to Eureka, then Eureka to Fresno after a 3-day agility trial.
1) You have to make campground reservations well in advance! I hadn't camped for years and did not realize this would be true, and everything on the Oregon coast was full. I ended up in an RV park that I picked for two reasons- vacancy, and WiFi. Had to back in at a 90 degree angle in the dark. 1b) (Just remembered it) This was the only place I've ever had to use an adapter on the electric and I didn't have one. Now I have one that I never use.
2) The door kept popping open and swinging around while I was driving, even though it was locked. (The following year I put velcro on the outside to keep it in place.)
3) If you don't have any way to level your trailer, sleep with your head uphill. (No fridge
so not a problem there.)
4) Don't wait until the last minute to gas up- I had to pull into a tiny service station with no room and get an attendant to save a space for me so I could pull in- it was too busy, no room to maneuver, and no gas to go anywhere else.
5) The thing I worried about most, backing into my garage, proved to be a non-problem. The trailer fit!