Originally Posted by GREASYHANDS
Do what feels right
You'll get a feel for it once you start driving around a bit. I've taken a few different Jeeps out there and with an auto I normally for 4HI and just stick it in DRIVE. Some hill climbs, if I know momentum/speed is going to be an issue at the top, I'll get as much speed as I safely can at the bottom and then before it bogs down throw the trans in 1-2.