WI to Asheville, NC

There are several Interstate routes to Asheville and they all have a few steep hills thru the Blue Ridge but you are in and then out of them fairly quickly. Every size and type of vehicle and rvs go thru this area daily with out a problem. Just don't ride your breaks going downhill and stay in the slow lane going uphill. Out in the Rockies there are Interstate passes that are over 9000' but in the south east nothing much over 3000'. Mt Mitchell in North Carolina is the highest peak East of the Mississippi at 6684'. But the Interstates don't go over the peaks, they mostly cross thru the lowest points or gaps. There are local roads thru the Blue Ridge area that are much worse to drive so use the Interstates. However, you didn't mention the time of year. All the routes thru the mountains can have freezing rain and snow when its only raining down below, so if you are headed that way in a cold time of year watch the weather very closely.