The second tank should not be a problem just have to buy the base plate for a 2 tank system.. and replace the single base plate with it. You have enough room BEHIND the propane tank(s) for 2 batteries... I had a welding shop make up a L frame bracket and weld it in for my 6 batteries... photos in the mod's section..
2004 Chev Silverado Duramax optioned past the max. 2009 Jayco Eagle 308 RLS 765 watts of solar, 6-6 volt batteries (696 amp hour), 2000 watt (4000 surge) whole house inverter.
140 days boondocking in 2016
211/2015, 196/14, 247/13, 193/12