We have been in Walmart lots where there were no trucks and the other rvers did not run their generators too. Many Walmarts are also next to neighborhoods and I don't think the neighbors would appreciate you running a loud generator. If we run our generator, it is to make a pot of coffee in the morning and quick warm something in the microwave - it is quiet and we use it maybe 15 minutes. If it's going to be HOT - we book a campsite to have power and run the A/C -- Check out passport america - maybe you can get cheaper campgrounds along your route for power.