do you have a 30 amp or 50 amp setup? A 50 amp setup has two Hot "Legs" one of which could be "dead" accounting for the batteries not charging from the shore power or the generator. The live"Leg" could account for the microwave working.
If you think that the batteries are drained of charge and you can get to your house batteries then jump them or borrow a battery charger and hook it up . Make sure your shore power is not plugged in and your generator is not started and for good measure don't start the chassis engine.
I couldn't agree more that you need to get a meter. With just a little deduction all this discussion will become unnecessary and you will have the knowledge for the future.