Glad to have you here with us. Congrats on your new 5er.
6 volt golf cart batteries will definitely be better. If your inverter is large enough you will be able to run the tv. A roof mounted solar panel will be less of a hassle. I would look at a minimum of 200w. The more you have the faster you will re-charge.
Good luck and Happy Trails!!!
Tony & Ruth........... FMCA#F416727
Newmar Dutch Star 4320, Spartan MM Chassis, Cat C9, Jeep Grand Cherokee,with Hemi, hooked up with a Blue Ox Aventa LX, and Brake Buddy.