Solar chargers vary greatly in size, from small trickle chargers - some of which barely keep up with the parasite loads (smoke detector, propane detector, fridge circuit board), to others capable of powering large inverters for running a variety of 120v appliances.
You need to give us a better idea of what it is that you want to do with the 12v, both during the day, and at night. Colorado mountains can get cool, no, make that down-right COLD at night, and if you need to run the furnace, the furnace fan and control board are among the biggest 12v power hogs on the average TT.
I did a "big" solar power system last year, well documented in the Modifications Forum, and I can try to answer any specific questions that you might have.
On Edit - Ken makes an EXCELLENT point about reducing load being as or more effective than generating battery recharge.
2014 RAM 2500 Laramie 4x4 Quad Cab w/Cummins Turbo Diesel, 2009 Rockwood 2607, and 3 'yaks!
300W of Suntech Solar, a Rogue MPT-3024 Controller, and a Xantrex PW2000 Inverter