We stored boats and RV's for 8 years, then purchased a home that we now store on site. We stored in (secure-monitored) ( a true joke) Had items stolen, damaged, etc. with no obligation from the storage lot to help with anything. You sign an agreement that they are not liable.
We now have an acre lot with lots of RV-Toys garages. Would move before I would store anything again.
This is just my opinion. I am sure there are good places to store. I would only consider storing inside if I had to again.
There are alarms that you can install that will go off with movement, or attempted entry (that might help)
If you store, take everything that is even remotely valuable or that can be removed with you. We had props, batteries, fire extinguishers etc stolen. Anything they could remove they seem to get to and storing is not cheap.