Get yourself a recovery strap. Something stretchy. It should have no metal on the ends. If a strap with a metal hook comes loose, there's a mean projectile coming your way!
If you can't afford a winch, get yourself a come-along. It's basically a manually operated winch. Slow and sucky, but better than nothing.
Get yourself a shovel (entrenching tool works well and is compact). When you need it and don't have it, you'll kick yourself. Trust me.
Something to start a fire with, especially if you're wheeling in a colder area.
WATER. Take at least 2 water bottles per person. Odds are you'll never need it. But if you do, you'll be glad you have them.
A few snack bars, again, just in case.
You'd be surprised at how hungry / thirsty you get when confronted with a "surprise camping trip".
Also, cram a half-roll or so of toilet paper into a ziploc bag, and shove it under the seat. Never in the way, and always there.
A small first aid kit is a good idea, too.
Some basic tools, dependent on your mechanical aptitude.
Ditch the Hi-lift, they can actually be dangerous to use. Get about 12-18 inches or so of 2x6, to give your stock jack a good base if you need to use it in soft sand, mud, snow.
And check your spare, make sure it has air. I've seen many people grab their spare tire only to find it's flat.
But first and foremost, get a wheelin' buddy. It's always best to have 2 or more vehicles.
Oh yeah. Duct tape.