We have 5 fur babies, and generally take two at a time with us. The other 3 stay home and the neighbors watch them. We rotate which ones get to go, and all of them are perfectly happy to hang out in the motorhome while we're out... the AC stays on if it's hot, otherwise we leave a fan running, and there is always plenty of food and water.
One thing I didn't see mentioned is security... we feel good knowing that there are dogs with us who have much better senses than we do. If we are forced to park in a Wall-Mart to get some rest, we are REALLY happy that the dogs are with us!