Climb the obvious wide chimney left of Jaberwocky.
Go deep back in there. At the top of the chimney there's an arching crack out right. (You can see this from the campground actually.)

From the top of the chimney, I suspect you can go left onto the wandering original route up the dome.

Chimney is knee butt with no pro and a slightly hinky move in the middle as there's a small roof that causes the size to step down. I think you might get some gear in above this move. But it's pretty straight forward climbing.

Upper crack is pretty cool 5.8 and puts you on top of the Abra summit. (NOTE, not the true dome summit, but top of Abra.) Still have to do that last nasty boulder bit to tag the real summit.

I'd raved about this arching crack to Steiger and convinced him to go up there. "Good Zzzzs" because we were on top by 10 AM or so and ended up getting sun burned from napping on the summit area. So what I was expecting to be another test piece turned out to be probably the easiest way to the top of the Rockfellow dome.

I've heard that Gary Gray might have climbed this in the 79/80 but I don't know about that. We didn't see any signs of a previous ascent but that doesn't mean much. The climbing was well within Gary's abilities. From the top of the long chimney (I can't recall if that was only 1 pitch but I think it was) I suspect you could go left onto the original McCoomb route (I'm forgetting the name of that one at the moment, the original line to the summit.)