Get a 12VDC fan and run it off you 12VDC accessory port. If you only have one battery, you will need some way to monitor the voltage (should not let the voltage drop below 12.0VDC) and charge your battery everyday. At some locations in the mountains you can not use a generator so you may need to charge your battery using your TV to charge it.
Order a digital voltage display something like the one below on Amazon, they are inexpensive, it will let you know when you can no longer use you battery until it gets recharged. Do not use the USB chargers unless you have a fully charged battery.. but in the mountains you may not have cell service anyway.
2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package
Our Solar Album http://www.jaycoowners.com/album.php?albumid=329