The selector is on the right hand side, and yes that screw in bolt is
on the side on the right. Basically, if you push the selector forward you will hit the screw, remove it, and it will allow you to go into creeeper.
People use creeper it for tilling. I never used mine.
I don't have the 1720 anymore, ended up getting a 226d with a loader, the 1720 was in much better shape, but the 226 had the loader, and I didnt feel like switching them. In addition I noticed the frame on the 226 is thicker than the 1720, since I am using the loader, I thought the thicker steel the better.