Actually, TBI swap isn't too bad at all. Esspecially if you have a complete parts vehicle
Biggest problem you'll run into is going to be fuel delivery. TBI needs 12 - 15 PSI to operate correctly, and a stock mechanical pump only provides about 4 - 5 PSI. So, you'll need to either replace your saddle tank (s) with the tank from the suburban between the rear frame rails, get yourself an 87 EFI saddle tank (or two), or just install an inline fuel pump. You'll want the pump as close to the saddle tank as possible, as they are built to push fuel, not pull it. If you have dual tanks, you'll want to install it directly after the diverter valve, behind the pump is suction, so no worries about leaking diverter valves etc. Infront of that, you can use your 88's fuel lines to run from the throttle body to the frame, use it's filter etc.
Less the fuel delivery, the only other major challenges you'll face will be how you mount the intake (swap to the 88 heads, or modify your intake's center 4 bolt holes to fit the older heads) and the electrical (again, shouldn't be too tough if you don't cut any more wires than you absolutely have to)
Keep in mind that TBI isn't built for major horsepower, but more for low end grunt. So while Vortec heads may be great for high horsepower applications (and even there they arn't that amazing) they may not be worth the money for a TBI 4x4. If I was to switch heads, I'd look for a set of f-body L98 heads. I can't remember the casting numbers off the top of my head, but they'll be found on any 350 tuned port engine. The Corvettes actually had an aluminum version of them! The heads come in two version -- Center and perimeter bolt valve covers. You'll want the centerbolt covers so your TBI will bolt straight up.
As far as a camshaft goes, all the different cam manufactures sell EFI cams, and I would HIGHLY reccomend putting the extra money down on one. You can get cams for these TBI engines that don't require and chip changes, but will wake your engine up a whole lot. The biggest thing with the EFI cams is their lobe seperation angle. They need to be a numerically higher number (112 - 114 is best, more torwards the 112 mark) or you'll get a very rich idle.
Oh, one more thing, Vehicle speed sensor! Make sure you don't skip this critical component -- Esspecially when they are as easy to install as they are in these trucks!
Just take the yellow wire that goes to your cruise controller from the optical sensor on the back of the speedometer, and feed it into your ECM, problem solved right there! If your truck doesn't have cruise, thats alright, your speedometer head is setup for the VSS anyways. Just give me a shout, and I'll have a VSS in the mail for you for the cost of shipping the next day