Are you kidding? If you are referring to the Rock Creek trailhead (Mosquito Flat) north of Bishop, then the one-way mileage from there to the summit of Whitney is about 130+ miles. So...over 260 miles in six days, including multiple high passes? Possible, if you are an ultra-marathoner and have support crews.
Or is it another Rock Creek to which you refer?
Rock Creek is a drainage into Kern Canyon just SW of Whitney (one of the areas of SEKI where bear canisters are REQUIRED, BTW) accessible from Cotton Wood, Army, New Army etc. I haven't done it, but its Trip 81 in Sierra South . 6 days to Trail Camp (pretty modest daily mileage) . Looks like it could be done out and back in 6 days, but if I were doing it I'd shuttle between WP and HM and go one way.
If you really mean just from Rock Creek, as a side trip, then its an easy RT, but I am assuming you mean from the TH, by way of Rock Creek not just from Rock Creek.
