gota think about how slow its gona be.
it might run 2 hours, but it also might take 2 hours to go 5 miles.
all depends on what kinda speed your gona be running.
id maybe look into a 2wd slash, with a stock/spec brushless, and get the biggest lipo you can find.
i know theres bigger than 5000mah lipos out there. or just have a couple 5000's extra with you.
on my scx10 with vxl brushless, i could get 45-50 mins on a 3200 mah lipo, but thats actually trail crawling. not very much wide open throttle.