The problem is the OP has a two wheel drive. In the 2wd, you don't have the low range capability of a transfer case.
I don't think traction will be a problem; I used to pull my 12K fiver up a similar steep hill on gravel in a state forest. I would have minor problems with traction in 2wd but not 4wd. They now paved that one section of the road and there are no issues in 2wd. I can tell that the truck is straining to pull it because of being in the normal gear range on the transfer case.
Just to be clear, the driveway runs downhill to the pad. So my thinking (plan?) is to back the rig down and then drive forward up and out. Any concerns about backing this combo down the hill? Thanks again, Steeve
If you always find the answer, try asking harder questions....