Hey ya'll. Looks like you're off to a great start. double to what everything Stryder says (his truck, and outlook are on point)
My idea with the truck is there's two ways to do things for any given part- extremely overbuilt custom, or overbuilt off the shelf. If I can find it and it works, I prefer off the shelf. I don't ever want to break something and not be able to find it in the local area of wherever I'm at in the country. Of course, sometimes you got to build it up yourself, and in those cases, build it so it will never break.
Only thing I would say is be careful with upgrading parts before thinking about what the next weak point is. RCV axles would be a big no-no on a 8.25 front end(and I would even argue a 9.25). Carrying and replacing a CV is a 20 min wheel-on job, vs. replacing a diff or losing 4wd out on trail. Same goes for the larger front tie rods. Personally, I'm a fan of the sleeves on quality tierods (Moog/ AC Delco) vs. the beefy units. We ran across a silverado recently on trail with some upgraded tie rods that had it's steering box ripped, Again, would much rather bend a tie rod and replace, then deal with that. Your next point of breakage after the tie rods are pitman/idler and then steering box. The steering box is pretty stout, and with some help the idler/ pitman are too. Of course, there's a point where if we were bending tierods all the time, then we'd re-think, but that's not the case. We run pretty fast and haven't had any trouble with the front ends with a combination of sleeves on quality stock size tie-rods, quality pitman arm/idler arm with cognito braces. The (not so) weak point is still the tie rods and I like it that way. For the CV's- if you go to a six inch lift you can fit a 2500 front diff and axles in there- if you stick with the 8.25 there's not much to do other than just be careful with what you're doing. The front end isn't that weak with stock tire sizes or even 33's if you stay away from the throttle pedal when stuck, it's the bigger tire sizes (especially with aftermarket uca and extra droop without limit arms) where it gets into trouble.
For the gas tank, look over on my build thread for some pictures. a 1996 F150 gas tank fits perfect where the spare is. Bought one with the built in pump and plumbed the output into the filler for the stock tank (got a gauge off ebay too!). Also the angle works perfect to plumb the aux fill into the stock gas cap door. In a pinch, if the main tank was ruptured, I put quick fittings on the output for both, and can confirm the f150 tank will run the truck.
For the brakes- Fronts- A HUGE upgrade is fitting the GMT900 brakes to the front end(look at my thread or around for the exact year that is best- can't recall off the top of my head). I can't say enough how much of a difference this made, with bolt on parts. Also- again the thing I love about it, is any part store in the country will have on hand replacement parts. I can recommend the AC Delco police line calipers, rotors and pads. Brakes are a tradeoff (bite, heat, noise, dust, etc.) and I think that line is the most aggressive- non squeaking pad for this truck I've found.) I think on rock auto for everything it was less than 400 bucks. The only downside is you need to be on 17's to fit in the wheel. (All three the Burb's have $150 craigslist GMT900 wheels). The rear brakes on a GMT800 suburban are the biggest ones that were fitted that will fit bolt on- (even bigger than latter year 2500.) For those just get some good calipers, pads and rotors (again AC Delco Police are what I recommend)