slman,
I don't think removing the tires for storing is overkill in your situation. Trailer tires need all the help they can get.
A few years ago, I read a "Trailer Life" article where they recommended putting the rig up on blocks and airing the tires down to 10 psi.
For maintaining the coach, I always leave the roof vents open. It needs ventilation. Also, as commented here, moisture forms when there is a temperature change, or difference of temperature between the inside and outside.
A few years ago I stored my older trailer in the Northwest for the winter. I covered it with a nice trailer cover, then with a big Harbor Freight tarp over that.
Big mistake! The lack of ventilation corroded everything. It was the hardest winter in that poor little trailer's life.