No power to coach -- 1996 Four Winds Class C - Help!

If you are using a standard extension cord. It will only handle 15 amps at best. Not enough to run AC and other items. Get a cord rated for 20 amps. You may have blown the circuit breaker feeding the extension cord.
Even though end of 30 amp cord looks similar to a dryer or stove plug. Do not plug the RV into it. These items are wired for 220 volts. Not 110 volts that the RV is wired for.
After AC shuts down. Most have a delay of 10 to 15 minutes before AC will run again.