Yes, you can do it in a couple of hours...if you do it right the first time, instlling the U-cup seals facing the right direction and don't have to look for some spring that flies across the garage when it's taken apart.
You may not need a rebuild package, just inspect the old parts, clean and reinstall.
The piston within the slave cylinder has a valve in it, which must be operational (it is part of the rebuild kit).
The long spring in the slave cylinder is easy to kink and may have to be replaced if it does get kinked (also part of the rebuild kit).
One TM shows the U-cup seal for the slave cylinder installed backwards. Remember how the parts come apart, reinstall the same way. The cup of the U-cup seals must face the high pressure side.
Use brake fluid to lube the parts when reassembling.
NOTE: I cut an opening in the tool box to gain access to the control valves of the Airpak without even taken the unit off the truck. Possible to check operation also.
Bjorn