You are much better off bolting the solar panels to the roof, and it will keep your battery full while it is stored, and the battery will last much longer.
You use more power than you think. It takes 35 amp hours to run the CO and propane detectors and the refrigerator, and anything else will just add more load to it. That is about what one of my 120 watt solar panels make each day.
Check this location for a good price.
SunElec.comLook for a 12 volt nominal panel with a aluminum frame. They had a 140 watt panel a few weeks ago for $229.
Good luck,
Fred.