Based on what I can see, the best training would be to get comfortable being wet, cold, hungry, frustrated, and sleep deprived.
I'd plan to stay up for a day and half when rain is forecasted. I'd probably shovel dirt from one pile to another then back again, chop a lot of firewood in the rain, take a long walk in a woods at night and wander local creek beds for hours. I'd try to eat as little as possible. When I was ready to quit I'd probably force myself to sit in the rain and do a crossword puzzle with a pencil that has a broken tip.
The closer you can get to being comfortable with complete demoralization the better off you'll be when you're in VT.