"I've read that some folks with a full solar set up don't even plug in when it's available." I don't usually plugin except when I want AC which is rare.
"All the tech details freak me out so can you give me an idea of what I would need to go mostly solar?" Use a free online RV solar calculator to determine how many amps you use per day then add another 50%. Then you can determine how many solar panels and the necessary battery bank required to store the power.
"Would I have to have different from my 2 middle size deep cycle batteries." Yes, more than likely you'll need new, larger capacity batteries.
"Best, I assume to have the panels mounted on the roof?" Yes, then there is no set up, take down or theft issue.
"Could I run the AC, even at night?" I've heard about RV solar systems that can do that but never seen one. Due to the necessary battery weight I believe it is not practical.
"Approximate cost?" WindyNation top of the line 400 watt kit with MPPT controller $850 plus another $100 for wire, glue, screws etc. Say less than $1,000.
"Would I give up anything?" Yes, generator noise and maintenance. However, I do carry a small inverter generator for cloudy days but haven't used it in 60 camping days except for exercise. May need to this trip!