Shouldn't be a problem. Did it in a group of 3 last summer with double 60s, but there is an intermediate anchor maybe 50 feet down and to climber's right from the top of the route that will get you down if you dont have enough rope.
You might be confusing Moscow with Super Slab. Moscow is a walk-off, Super Slab is most definitely not a walk-off unless you're willing to do some super sketchy, unprotected solo traversing. Super Slab can be done with the two ropes you have.
Definitely not confusing them. Go back into the gully, climb a bit of fifth class slab, continue on easy third class terrain to the Playhouse, follow the path to the trail. It's well detailed in the guidebook and faster than rapping, especially if there are crowds.
I will agree with Dobson that the walk-off is not bad at all. A short unexposed 5.0 downclimb into the gully. Then a 5.6 slab/corner out of the gully. Most solo the slab but one could belay as well and there are bolts at the top of the slab to bring up the follower. None of this is exposed or you are going the wrong way.
To rap with two ropes use the anchors on Amphetamine Grip which are 50 ft. to the right (North) of Super Slabs finish. Then another rap from the top of pitch one of Super Slab. Two 50 meter ropes should be long enough although I did it with two 60 meter ropes.