buddy
What is a rattle snake? I see garden snakes, mole snakes?!?!?! among the two that live around here. No rattle snakes.......unless it got loose from somewhere, then it will not survive too long due to colder temps....I've also never seen a mole snake or whatever the 2nd snake is that lives around here, so not too worried about one of them either.
If you are worried about going up the hills, as much as down. I have some formula's somewhere that show what gearing based on tire diam you need to go up an x% grade. My old 6.5td with 4.10s and the NV4500 with 385lb ft of torque was good to 30% at 20K. Where as the POS 4l80E was good to about 16%, if that. A Dmax with 600 lb of torque, an allison is good to about 25% at 20K lbs, and around 40% with the ZF6sp. Tranny gearing itself can do a lot vs just looking at axel gears.
With this in mind, the GM 6l90E has a 4.10 first gear, put that with a typical 3.73 or 4.10 axel gear, 31" tires, a TC around 2-1 with a loss of 20% for heat and slippage, you have a pretty low overall low in the 28to30-1 relm. Better than my 96 at 24-1. You should not have any issues going up hills that are typically found on side roads, forest service roads etc. The issue will be the going down, but as noted, even with a manual, some steeper grades in the less than 5mph range, you needed the service brakes to slow down etc.
Marty