I have a 301a and I just ordered the hopping for it from sew classic . I intend to put mine on my original little gracie frame when I get it all put together. I had already found a slant shank walking foot for it, before I even had the machine. I picked it up at a yard sale. I just couldn't leave an older singer walking foot there, even if I didn't have a machine for it. 😃
I also saw a video of a woman using her regular pressing foot to do free motion on her 301. She was just zipping right along. I don't know if I would feel comfortable doing that.