Converting a class C from 30 amp to 50 amp service

I have a Winnebago Via that is 30 amp, and added a heavy duty outdoor extension cord under the bed to the utility compartment. I connect the extension cord to the electric post at campgrounds so that my wife can use her hair dryer with the AC going. If needed, I could use the extension cord for other appliances. Not every campground has an outlet on the post for extension cords, and if you cannot route the cord behind panels or beds, it could look messy. Works for us.