It's difficult to recommend the "best" storage solution because the best storage arrangement is different for each individual. I prefer to keep my RV at home. The trailer has it's own parking area with water, electrical and sewer hookups. This makes it easy to prepare for camping trips, do maintenance work and I get to sit in it just for fun.
Your idea of covered parking sounds good. I use an ADCO cover which works well during the winter but I do get intense sun exposure during the summer months. My friend parks his trailer under a carport pole barn structure and it works great! The carport provides excellent UV protection during the summer. It's a good idea to reduce snow, rain and sun exposure as much as possible.
For the electrical question, during the winter when my trailer is covered I use a 100 watt portable solar panel to keep the batteries charged. My trailer has a battery disconnect switch that turns off 12 volt power to the trailer. During the winter the 12 volt power to the trailer remains off. When parked at home or at a storage facility you want to keep the batteries fully charged.