I havent driven the adventra at length but ive offroaded in many different 4wd's in the past. With careful wheel placement its amazing how far just a standard 2wd sedan will go.
In my experience, u'll get by 95% of the time and there will be one section of track that will require a real offroad vehicle. I spose the roughest thing youll encounter is camping, so if thats not too hardcore itll be ok.
Rubber is VERY important!I got a nissan patrol stuck on the side of a muddy sports oval once (unloading gear) because it was the standard semi all terrain rubber. If u see slippery surfaces a lot, BF goodrich now have small all terrain tyre sizes.
I did an experiment with a friend, hill starting on a grassy paddock in 2wd, I had standard rubber, he had all terrain style- I was spinning my wheels, drifting backward and he could take off with no problems- he couldnt even get it loose traction!
If u get all terrain tyres SLIGHTLY oversize youll see better grip, increased clearence, less punctures and a more comfortable ride. But beware, offroad tyres dont handle as well on wet sealed roads.
The only other disadvantage for adventras is lack of low range, but the torquy v8 should make up for it in most situations.