I have Maxxis tires and am very satisfied. I went to my local trailer (not camper) dealer and got a set of 4 tires already mounted on rims. Not much more expensive than taking tires to dealer, but lots easier.
Don't use the stabilizers as jacks. Don't jack up by the axle tube. Either jack up by the frame near the tires or where the axle is attached to the springs. I use a Trailer Aid. Use of jack stands is a good idea, also.
No silicone caulk on the outside. Dicor or the like is better. I don't use it on the inside, either.
The manual for the camper is usually generic and fairly useless. Better to get a loose leaf notebook and fill it with info on all the separate components. Get model numbers and go to the fount of all knowledge(The Google).
Get everything weighed and learn all about the various weights of your camper and your tow vehicle.
Good luck and Happy Glamping.