1989 DS Torque upgrade Questions

[DeerJerky]

Hello, I am new to this board as well as the Golf Cart restoration world.
I have a 1989 36V DS with the resistors back by the motor (no electronic speed controller). The batteries are bad so I am going to be replacing them. My sole purpose for this cart is to get me to my hunting spot which is up a fairly steep incline for about 1/2 mile. My question is, what can I do to increase the torque on this cart? I don't care how slow the cart goes, I just want to increase my torque so I can get to the top of the Mtn. As I have been studying the posts on here and other sites, I have come up with some questions:
1. Can I replace the 6 volt batteries with 8 volt ones to get 48 volts? will the stock motor, and other parts handle this?
2. should I upgrade the battery cables to bigger cables? If so, do I replace just the battery cables or other ones too?
3. can I change the gears in it to increase torque?

Mechanically and electronically I can handle just about anything. My only limiting factor would be cost somewhat.
Any suggestions you guys have would be great.
Thanks in advance for your patience and help,
DJ