Another take....
I used to be big on coasters. Something changed in the last couple years though (I'm now forty, must be age!), but I no longer care for coasters. Space Mountain, which I used to laugh at, now seems bumpy to me.
That said, I can't say you'll have an enjoyable experience on R&RC, but it won't ruin your day. It's fast, it's got lots of twists and turns, but as Luv2Roam writes, it's smoother than your average coaster and the best way to face it is as relaxed as posible (in my case, with eyes closed, but you miss the theming that way).
I would make two suggestions, from direct experience. First, the "worst part," or best part if you're young either in chronology or spirit, is the "blast off." You'll hear Steven Tyler making the countdown. When he says blast off, you do. THIS ABOVE ALL ELSE IS THE TIME TO BE RELAXED. After that, it's really cake.
Second. Do NOT visit the turkey leg stand immediately before riding. Trust me.
All in all, I don't go on this when I'm alone or with my wife, but if we meet up with my niece and nephew, I ride it without any ill affects. Go for it!
Pat