QueenBee, I just rode the GAP and used cycling shoes with toe clips. I did have a bit of numbness, but it grew less and less each day. We were on the leisure plan, so when it got annoying, we just stopped for a bit and had a snack or watched the red tail hawks cruise along.

FWIW, I have clipless pedals on my road bike, but view the hybrid more as a "hop on and off" kind of bicycle. I ride to the pool with my kid and want the flexibility of wearing any shoe that I happen to have on at the time.

Enjoy your trip!