Violent shaking in the steering wheel

I agree with carringb full front end inspection with brakes. Also check all tires not just fronts. Then after that go get it weighed total weight and weight on front and rear axles. Best to get it weighed loaded for a trip but that can be done later. IMHO class C motor homes are prone to under loaded front axles and the longer the motor home the more prone it is to this problem. Any weight on the front axle that is less than 75% of it's rated capacity is under loaded. One classic sign of under loaded front axles is a floating feeling and is extremely hazardous. If you are under loaded then you need to move weight forward. There is an effect called the see saw effect and what that means is any weight behind the rear axle takes weight off of the front axle the farther back the higher the effect.
Alignment is in order I am sure but it needs to be loaded for trips before alignment.
Please keep us posted on what you find and what you do it can and will help the next person