Thought I'd fill you in on my true maiden voyage.
I recently moved up to NJ from Florida. I've had my envoy out on the beach/back roads, but my experience was pale in comparison to some of the stuff I see on this site.
As per Gordinho's suggestion, I finally got out to Wharton State Forest.
My girlfriend, two dogs, and I headed out of a night of camping and two half days of exploring the forest. I was a little worried about getting stuck.
I currently have Mark's 2.5" lift, but that's it! 3.42s, stock street tires, no G80.
We got there and most of it was "unimproved sand roads." Honestly, I was a little happy about that.
Few hours of this:
We had to get to the campsite before it got dark to set up.
We hit a huge puddle/mudbath on the trail to the campsite. Not taking that trail meant backtracking 2 hours. No thanks.
We weaved through some trees and got onto a parallel trail, only to find that trail ALSO had some deep water. We hugged the side of it. Water was up to the body moulding on the doors on the driver side. Got through! I was quite happy - and pleased with my envoy. Half of me (OK - more than half of me) was expecting to sink in the mud and get stuck there!
Here's the puddle(s). I wish I had a picture of me IN IT. Maybe next time!
We made it to the campgrounds. Camping was not really as I expected. Campsites were all very closely spaced. But we lit a fire, cooked some hotdogs and baked beans, and got some sleep...
On the way out we explored the northern part of the forest. Seemed like more sand, but we hit some dirt along the way.
There are a lot of deep mud ruts / mud puddles around. I suspect that if we got rain, it'd be pretttttyyy muddy. The whole forest (at least what I saw) was very flat. Little rocks.
All in all, though, it was a great first experience. Not as daunting as I had imagined.
I learned a lot. Some of those major points:
1) Street tires are just that. I need something better!
2) My Envoy is more capable than I gave it credit for.
3) Don't buy a small tent and expect a good night's sleep with a girlfriend and two dogs.
4) Bring chairs. I pictured sitting around a campfire... I'm not sure what I pictured sitting on.
I've been debating what to do with my Envoy. I'm hitting 130k. I drive 120miles daily on it. I've always thought I didn't want to put money into it and have it explode - but now I'm having second thoughts.
Only issue so far from the trip, is that I found out my back right axle seal/bearing need replacing. A little squeaking and gear oil is dripping out. I'm topping it off for now. I'm trying to find somewhere to do the work. My current apartment complex situation is not cool.
Anyways, thought I'd share.
I'm happy about the trip!
Also, if you're going to encounter water you want to think about extending your breather tubes on your differentials. Other then that, bigger tent! 
Glad you had a safe and fun first trip. 
You'll find out that is a trend, trip - mods - trip -mods... 
Nice write up by the way. 
They wanted $95 a piece when I looked for them at the dealer, make certain they're for the trailblazer then pounce on them 
