Ditto on the covers and the palm trees. I don not have the option of palm tree storage either :( . Besides rubbing the trailer finish, covers can also rub through and tear wherever there are sharp points (corners, awning rails, antennas...).
I feel that the RV antifreeze should be left in the lines to keep the fixtures and pump seals moist. Have never had an issue with doing this.
As for keeping mice out, I have never had much of a problem. Some people recommend dryer fabric softener sheets, or squirrel pellets. I just make sure I have everything edible and all soaps removed and fill any openings or gaps with expanding foam. If you store inside, you can also put D-Con aroung the inside walls of the building, not the trailer. Good Luck!!
Rick and Janice Binns
2006 MS 32TK3, Mor/Ryde Pin Box and I.S., Auto Level-Up
2012 Ford F450 6.7 L Diesel, air bags and 25K Reese Signature hitch (factory installed)