Don,
The only way to properly diagnose your electrical problem is to take a voltmeter and start checking circuits. First check the shore power plug to make sure that the neutral and power wires are not reversed. Next check your 30 amp to 50 amp adapter. If you have a spare adapter, you can just try the other adapter to see if this repairs your problem, since they have a high failure rate. However since you said that you heard the Surge Guard activate, this probably is not your problem.
Since your Surge Guard and transfer switch is a combined unit, I would start by checking the incoming voltage between the hot leads and the neutral lead at the Surge Guard. You should also check between the neutral leg and the ground wire to make sure that there is no incoming voltage on the neutral leg. If the incoming voltage checks out OK, your power cord reel, 30 to 50 adapter, and power cord are OK.
Next check the voltage on the output legs of the Surge Guard in the same manner that you checked the input voltage. There will be no need to go any farther, because you have operating voltage in the coach from the generator, so everything after the Surge Guard transfer switch is OK.
Gerald