The single best thing that can be done to keep a trailer new is covered storage .
A carport , 3 sided shed , and the covered open type of RV storage normally available all work better than the fabric RV covers .
The solar heating ( expansion ) during the daytime and then the cooling ( contraction ) at nightime work to create leaks at the panel joints and various accessory openings .
There are breakins at every RV storage facility over time .
Some are worse than others .
That is just part of the risk of owning an RV .
If you need to store your RV elsewhere than home then that is what you have to do .
RV insurance is the cheapest item by far on my premium .
They charge me 3 times the amount on my boat .