If you put the fridge and water on propane only I would give them a go. Maybe wait an hour or two for the battery to be full charge before you try the second. And of course don't start them at the same time. No MW, hairdryer, electric coffee or toast etc. New units are getting more efficient and may draw less power. Check your adapter is not melting from a poor connection to the worn out pedestal connector and always good to check voltage stays 108+ in the RV. If the main breaker trips off just reset and keep one off from that point.