If it were me I would take US19 into Cherokee. Wife and I rode over all that area on motorcycles, it's our favorite bikecation ride. The only problem is west of Maggie Valley it gets a little hilly and curvy. Cherokee is about 26 miles from Maggie Valley, about a 30 minute Bike ride, for an RV an hour or so. There is a long stretch of a mountain west of Maggie Valley, near the top is a passing lane, so be careful there, bad drivers tend to wait and pass at the last second. The downhill side of this mountain it is a pretty good distance and it has some pretty hefty curves as well. I say take it and take your time, make sure your trailer brake system is in good shape. I remember passing a many RV's of all types on US19 between Maggie Valley and Cherokee. Best time to hit that section is early in the morning, but that is not good for a check-in of 3PM, however, you do have a lot to see and do in Cherokee. Nice little coffee shop in a plaza area, place called Qualla Java nice place and great service. But then again do you want to drive a 32' camper in the middle of downtown?
I would not take Blue Ridge Parkway myself, for the simple reason there are tunnels and I don't remember the height restrictions. Although, I have also passed a many RV's on the Parkway on my motorcycle. If time is not an issue and you do some research on tunnel restrictions you can jump on the Blue Ridge Parkway just about any where. The scenery is fantastic, beautiful and worth seeing. Again the best time to travel the Parkway is early in the morning hardly any vehicles. Also, plenty of pull overs for breaks and site seeing.
Hope this helps