I have done a fair amount of crewing with tow vehicles ranging from
Suburbans to light Dodge minivans. The towing requirement included 15
meter gliders in higher profile (Minden-style) trailers as well as
Cobras and western mountain passes as well as lots of flat. My
impression is that the Suburban is overkill and there is just no need
for something with such high fuel consumption. If getting a Suburban,
I would opt for the highest mileage engine and 2wd unless you think
the retrieves will be into wilderness where 4wd is essential. The
Suburban does come with an option for an oversized fuel tank (I'm not
sure if it is limited to the 454 or not) and that does make it
convenient for some crewing in desolate areas like in northern
Nevada.

The light Dodge minivan towed a 15 meter glider in a Cobra-style
trailer very well by simply keeping the transmission out of overdrive
to minimize shifting up and down. Mountain passes were handled easily
up to about 7000 feet and speed maintained near the speed limit. The
fuel tank is smaller but the improved mileage about wiped out the
disadvantage.

I thought the Ford Explorer with the (earlier) V6 or (later) V8 was
almost an ideal tow vehicle. Inexpensive and reasonably efficient
with 2 or 4wd. I used a 4wd, V6 version with my own glider with a
Minden trailer.

The only tow vehicles I found to be deficient were a small Chevrolet
pickup with the 2.4 liter V6 and a Mercedes 300 diesel sedan without
the turbo charger. They tended to lose too much power at higher
elevations. If you are in flat country they would both work fine.

Greg100