i'm kinda in the same boat as you on deciding on a vehicle. I'm a newb to this sorta thing so my input won't carry much weight.
for me I chose to go the 5.7L tahoe route. for minimal mods there seems to be some decent factory packages out there to get you started with upgrades down the road.
I picked up a '00 tahoe Z71 on sunday, this is the old body style. not 5.3L types.
comes stock with
5.7L Vortec
3.73's,
G80 rear posi (10 bolt)
265/75/16 -decent starter size (32")
tow package - trans AND oil coolers
rear barn doors - required for OBS trucks
appears to be a tad higher than regular 4x4's but that might not be true.
with the 2nd row seats folded forward there is 78" of space from the inside of rear doors to the back of the folded seat. I'm 76" tall... just enough. actually planning on pulling either the 60 or 40 side of the rear seats out & adding a small, level platform to get that extra lenth while yet having a seat for a 3rd person. the width of the tahoe and suburbans are the same, just a tad over 48" inside.
285/75/16 (33"s) appear as if they'll fit with minimal trimming. 14bolt semiflaoter from another 6-lug 4x4 will bolt in for extra towing strength. It is generally regarded that the tahoe brakes are weak. I'm thinking of adding the hydroboost brake booster to give more umph and maybe upgrade to 3/4 ton calipers & pads (slightly diff piston size though, more research to do).
on the 1st leg of my highway trip from dallas I calculated 19.3mpgs cruising just a tad under the speed limit and driving nice. After a few tweaks & tuning I'd be happy with 20. not sure what 285's will do to that though...
i'm selling a carb'ed '86 3/4ton 2WD that gets 12mpg at 65mph. so it is a down size and I really like the old stuff but i'm going to give it a go and see how it does for light expeditions & towing. stock ground clearance isn't something to write home about, not like my friends 2" lifted ZJ w/ 31's.
oh, has 133K miles and picked it up for almost 1/10th of the original sticker value. $4300