Problem starting my 1996 Bounder rv...?

sounds first like the voltage regulator took a crap, ( thats in the alternator ) it is not charging, you probably need a new set of batterys too, but you should also replace the solenoid first, that could throw off the voltage meter in the dash if it is not working right, a bad connection on any of the battery terminals would make it do that too ( not want to start ) clean them before you try the solenoid replacement