First of all - WELCOME. I hope you have years and years of fun RVing across the country.
In our fifth wheel we don't - we have to depend on the power supply at the RV Park or State Park where we camp. I can say in almost 26 years of RVing we have been extremely fortunate and rarely had a problem. Last Fall in Port Aransas, Texas a car hit a light pole and knocked out electricity for several hours. Even in the fall, the weather along the Texas coast can get pretty warm.
Thankfully we were at the RV with our two dogs when it happened. We were able to open the door and windows and stay fairly cool, but we also went for a ride in the truck (with the A/C) for part of the time. To the best of my memory, that's the only time in our camping history our power has gone out.