Welcome to the board
On the pipe you can't really get a aftermarket kit since the bends and turns are so tight with dealing with a 4x4. Best would be going to a shop in teh area and have it done there. A few things to remember is that if you have or going to be having emissions in your area you need to find out all the laws about them to see if the catalytic converters and AIR tubes are needed. This will narrow down you choices on headers and some options. If you need the cat then you will more than likely need to run a Y pipe from the collectors of the headers to the cat (mounted in stock location) then you can run duals off the cat the to a H pipe (not really helpful with a cat) and then to the mufflers. If you do not need emissions then you can get a H pipe added after the collectors. A boddy of mine has a 83 Blazer underframe and driveline that the shop ran a H pipe over the drive shaft after the collectors and after the transfer case. Then onto mufflers with pipe out back. Looks great, sounded good, and no clearance issues.
The H or X (another option but hard on 4x4) pipe helps equalize the pressure on the exhaust. The H is good for tight spaces like yours and creates more torque. X is better in that it helps in both torque and horsepower. I have an X on mine. Just make sure not to get too big or small diameter of pipe. Biggest on small block would be a 2 1/2" pipe and 3" on big block. Also header pipe size makes a big difference as well. Good luck