I have seen pictures of people running car batteries, after relocating them up front. Running two batteries with an isolater would be a great set up but a little more difficult to do. This would keep your starting battery charged and run the extras from a deep cycle battery.
If you are trying to run a stereo and a couple of extra lights, get the biggest AGM battery that will fit in the stock location.
05 650V2 LE, 09 550H1,04 Arctic Cat 50
"Every man dies. Not every man really lives" -William Wallace