Jim - During the months you mention, we have very few bugs due to the cooler weather. I wouln't concern myself with anything stored on the inside. I store mine in Tucson year round. Other than an occasional moth in the summer months, I haven't had an issue in over 10 years.
Depending on where you are storing it, you can have an issue with packrats though. They love to chew on wiring. Make sure there are no wood piles or pack rat nests within about 100 feet of your rig, and you should be okay.
Antifreeze is a good idea because we can get down into the teens or 20s on rare occassions.
2016 Ford F350 Turbo Diesel SRW 4x4
2017 Grand Design Reflection 297RSTS
2013 Ford F350 Turbo Diesel SRW 4x4 (Destroyed by fire - 8/29/16)
2014 Grand Design Reflection 337RLS (Destroyed by fire - 8/29/16)