Don't stress too much about what Bob said (Blackrock). I think he miss read your post.
Shelia is not disconnecting the batteries when she is at the park, rather she was wondering IF THAT would help them last as they go dead shortly after she disconnects and while traveling to the next park.
What Danny (Sourdough) said and Wiredgeorge. Your batteries are most likely toast and replacing them will most likely fix that. BUT load test them first to make sure. Most any auto parts store can do that for you. As can your local mechanic most likely.
When you replace them try to get Deep Cycle batteries as the best. However not always easy as they will try to sell you "RV/ Marine" batteries as Deep Cycle and though they are better than car batteries they are not true deep cycle.
(If the new battery has a listing on it for "cold cranking amps" and is listed as an RV/Marine deep cycle battery then it is not a true deep cycle battery. A true deep cycle battery is more like what they put into golf carts)If you cannot find true deep cycle the RV/Marine WILL WORK great for you as it sounds like most of your "camping" is done at RV parks and new batteries will be SO MUCH better
than what i suspect you have now. Will keep everything running while you travel from place to place. Leave them connected when you are at the park and plugged in. I disconnect mine when my TT (travel trailer) is in storage.
Welcome to the forum Sheila.