Well, it is important for a guy to have the occasional deep & meaningful conversation with his truck...take the relationship to the next level, make long term commitments, show support for cooperative growth, that sort of thing. For instance, adding an arseload of mods and learning how to rally the hell out of it.
Sorry this is kinda long but you're actually gonna put your truck to good use. Hopefully it ain't TL/DR material
.
The bigger your tire, the less space you'll have to move it around, and on such a new truck it'd be a shame to cut it so soon. Get the biggest tire you can fit, tho...it's more cushion, you can drop the pressure lower, like matrix-t was saying tires are a big part of suspension.
Pick up a CO2 tank kit from Ultimate Air, the 15# Express kit is the best deal for the money unless he carries a 20# tank...CO2 is useful stuff, some welders you can run on straight CO2 (the Passport was designed around it). It's like 270$, if you get it piecemeal it's over 300 for the basics. If you already have a regulator and hose etc. I know where you can get a new 20# tank for 140$. Trust me airing down helps a lot, and you'll use the CO2 for everything. Throw this in as one of your mods now, you'll use it as long as you have a truck, regardless what truck it is.
The compression/extension split is pretty important. If you set the ride height too low (like I did recently), you're on the bumpstops too often, and constantly hitting the stops will pull the alignment out (I should get a punch card for the alignment shop). 60/40 is just a ballpark number, you might not need that much uptravel, so mess with it (use a lot of grease btw or you'll gall the threads and they'll eventually seize). It just means, using that example on my truck, that of 10" total wheel travel, 6" (60% of 10") is uptravel and 4" is downtravel.
Sticking with the 1st-gen example, a stocker only has 6" of travel to begin with, and it's set at something like 2" uptravel and 4" down (the highest suspension lift is 4" on a bone stock 1st-gen). I ran a few easy trails like that, and was all over the bumpstops...it wreaks havoc on your alignment, makes you gun-shy for the next drop or bump, it's no good. With a 2" lift, there's 4" of uptravel, and I still found I'd hit the bumpstops on harder routes. Eventually I set it for about 4" lift and wasn't concerned with hard hits, plus the downtravel is strap limited and the same as stock (4") so it's soft on extension. Messing with it more, it seems like 50/50 to 60/40 works out very well on a 1st-gen with 10" of wheel travel...3" to 4" of lift. It's worth the hit to your vertical CG.
You'll find something similar with your 2nd-gen, but the travel numbers will be greater. The higher you set it, the stiffer it will ride and the harder it will be to align, but you can take a bigger hit. I don't know the travel numbers for a stock 07, but Total Chaos and Camburg should have numbers and good recommendations. Be aware the rear of the truck may end up low if you set the front ride height up 3"-4"...get the rear up there however you can and save for a full leaf pack (500 bucks).
Interco makes an SSR (I think) in 35.2x12.0R18, those are exact numbers on their measuring rim. If you can fit it (all the way up, turn lock to lock), get it--it's the narrowest 35" tire I've seen, everybody else is 12.5" or larger and you'd be surprised at all the problems 1/4" can cause. Otherwise get the biggest tire that'll fit at full compression and a full lock turn and no larger or you'll just give yourself headaches. They're in your neck of the woods, too...LA. They know gumbo mud.
Don't shy away from doing this yourself, it's not hard. Too bad you're not closer, it's about a day's work start to finish with beer in the middle. The benefit is you'll know what can go wrong, how it fits together, how to adjust the shocks, how to service the uniball and bushings, stuff like that. You'll need to know those basics to get the best performance from the setup, or you'll be paying through the nose to have someone else adjust and lubricate everything. You'll need a Factory Service Manual, or at least the relevant pages...the dealership where I bought my truck let me photocopy pages from theirs, Lon might have the pages here already, or you could buy one ($$$). Camburg, Total Chaos, Donahoe, all those guys can help with tips and pointers when you buy the parts.
Camburg and Total Chaos are very similar. Pick which one you like. You might be able to get a better deal with Camburg arms and shocks (by SAW), the other manufacturers are slowly closing the quality and innovation gap with Donahoe so you're not losing out by getting SAW (Camburg rebadges) instead of Donahoe, and since you're far from CA getting SAWs or another shock you can rebuild yourself (or locally done for you) is something I'd very highly recommend. If DR didn't go out of their way to make it so awkward for a buyer to service their own shocks, they'd be a lot more attractive to people who really push their trucks outside CA. If you're ok with voiding the warranty, they're as easy to rebuild as any other shock, and you'd just need a motocross shop with the right filling needle to pressurize them.
There I go rambling again and making a huge long post. Hopefully it was useful
-Sean