From our experience, most of the time when there is 50 amp outlets, there is also a 30 amp outlet. I'm sure there are exceptions, and if you are worried about it, a 50 amp to 30amp dogbone adapter should be on your rig. You might also want to carry a 15 amp to 30 amp adapter also, just in case you are parked at your house or at a friend or family's house and just need power for lights or just the fridge.
https://www.amazon.com/Adapter-Campe...ter+for+camper
https://www.amazon.com/Camco-Dogbone...ter+for+camper