Complete Hunting/Farm Cart Overhaul-???'s

[snobles]

First time poster...lots of good info on here...so much that I'm confused. I have a 1986 club car (currently 36volt, series, resisters)...that I've converted to a hunting/farm cart. She's updated on the outside...now ready for a complete upgrade on the electrical (here comes the $$$ part...batteries, motor, controller, HD F&R, etc). Here's my situation...I need to roam 200 acres (so I need long battery run time) that's slightly hilly with a couple of creek crossings. I'd like to travel at slower speeds (10-15 mph due to bumpy roads and kids holding on) so I don't want to be at half throttle all the time and burn up the system. I have 6" lift with 22" tires. I'll be hauling guys, kids, guns, hogs, deer, corn and pulling a very small trailer from time to time.

A local cart place suggested a two-speed motor but I heard the high speed draw ruins the battery life. I don't want to do wheelies or 25 mph...just want a smooth ride while poking around that has a long pack run time and good torque.

Here's my questions:
-36 or 48 volt best for this application?
-Considering GE Beast motor(D395)-seems slow and torquey
-Alltrax 500amp or GE 500 amp controller-need programmable (not sure)?
-Will be updating throttle, selenoid, wires (#4 or #2 ga?), and F&R

Thanks in advance for sharing your thoughts and insights!