TwistedPhil
+1y
-Shraeder valve in the tank in case the compressor dies
-Line/ Line coupler fittings (at least two) in the glovebox
-20 feet of air line
If you've got these things with you at all times, you shouldn't be stuck unless a bag blows. The shraeder valve is the same as a tire valve, so you can fill the tank up if your pump dies. The line and couplers can be used to patch a line or bypass a valve assembly.
Check valves are a great safety feature, but they slow the system down considerably, so you need to decide what your priorities are. Honestly, if your system is plumbed and wired properly, you shouldn't have any problems with reliability.
Good luck!