GP is an odd duck. It's a combo QS/TS place. You obviously can't make ADRs, but if you show up and there's no room to sit "inside" GP, then you can put your name on a wait list. It is often crowded with no table at which to sit, though you can sit at the bar and get the same menu. People also tend to linger at their tables more than most QS or even TS, especially during busy times. Some seats/tables are close together, so if you do manage to find someone who doesn't hog a whole area with just 2-3 people, then you may be sitting elbow to elbow with the other diners. The food is fairly good at GP, and it's a beautiful location. However, there really aren't many places to sit unless you factor in the bar itself. If you're a family of four or more, and you go during normal lunch or dinner hours, then you might be waiting for some time. As good as GP can be, it could have been much better.
As for Roaring Fork, it's a shadow of its former self. It used to be a very good QS; now, it's average at best.