Ramsey would probably ask why you're getting rid of the van, as it's almost always cheaper to keep what you got. That being said... if you've got the wife on board, the battle is halfway over!
I have a LWB Envoy. Seems to me that more of those survived (or were made?) than the LWB Chevys. If you like the SWB better, then the TB is much easier to find.
On a LWB...
- Make sure to check the rear spoiler; if it's hanging by a thread, the best way to get it fixed is via a new backglass, IMO. Or rip it off and learn to live w/o it (although it looks pretty ghetto, that way). Since you live in OH... teach the wife / kids to always make sure snow and ice are cleared from the top before opening the liftgate!
- If you can find one with running boards (again, more prevalent on the Envoys), the rockers should be in good (better) shape; they keep a lot of salt off the body. The worst area for rust on the body is the liftgate, in the bottom corners. It starts, more often than not, from the inside, so you have to pop off the rear plastic trim to see what things look like. If the thing has been driven in snow a lot, make sure to check the frame out, especially in the rear supports. That's pretty much unfixable, once they go.
- By '05, GMC had the Denali trim out, which integrates (different & better looking) running boards into the body, gives you some extra 'goodies', options-wise, and guarantees you the 5.3L. It's a great motor - but it's really shoehorned in. You'll also need to check on the gearset, as GM was fitting a lot of Denalis with the 3.42 gear, to help meet CAFE.
One thing a Denali will likely have (that might not be such a good thing) is the air ride in the rear. It's great, when the system is working, but the bags eventually leak, and the compressors go out, and parts are hard to find, besides (many replace with conventional springs). 1st sign of it going out is seeing the rear sag, after it's been parked awhile.
The front fascia looks better on them, b/c there's less of a gap between the bumper cover and body (one of the things I dislike most about my non-Denali, but I'm too cheap to replace it at the moment, and busy with my Sierra, besides).
If the wife likes a luxo barge, Denali might be the way to go for you guys. They're getting cheap, and they're fairly plentiful.