I know the thread was started over a week ago so not sure if you managed to select the tools you need yet. Many of the sizes for the 1/2 ton Chevy/GMCs are the same starting in '99/'00.
The main ones to have are:
*1/2" Drive Sockets:
-22mm[7/8"] - lug nuts (if still original), tie rods, lower ball joints.
-36mm[1 7/16"] - axle nuts
-18mm- brake caliper bracket bolts, upper ball joints, misc others.
-15mm - wheel hub bolts, misc engine, frame, skid plate and suspension hardware.
-T55 Torx - some calipers are mounted to the bracket with these fasteners.
*Note that if parts have been replaced such as balljoints, etc., the aftermarket nuts/bolts might be larger/smaller than factory. As an example, most lower ball joint nuts for the 1/2 tons are 22mm but some replacement nuts are 24mm.
For 3/8" drive sockets, you'll likely need 8,10,13,15,16,18,19mm depending what you touch under the hood and elsewhere (12+14mm are also common replacement sizes), so just buy a kit. Not enough weight savings to justify only carrying certain sizes.
Wrenches are also best to have a complete metric set. You never know what you need. Basically 8mm thru 24mm, skipping a 23mm since it's super rare. (And yes, 11mm is a must for ujoint strap bolts, lol)
There won't be any Allen (hex) sizes as far as I recall and if there are, a regular set of keys will do. So don't worry about buying Allen sockets.
Use your space requirements and best judgement on ratchets. I recommend 1 good sized (24+ inch) 1/2" breaker bar and 1 ratchet for each drive size you carry, but different lengths can be useful if not completely necessary.
Hope this is useful and not just overwhelming.
