I've posted on the walking foot for the 301 many times...not my favorite since any slant shank walking foot on the market is made for zig zag machines and they're too darn large for the 301/straight stitch machine. The feed dogs don't mesh properly and why bother, IMO. I would really work at getting your pressure foot pressure to release. It sounds like something is gunked up or stuck. Your pressure should release so much that you can quilt rather easily under it without a walking foot.
Or your foot has been messed with/lowered in height and there isn't enough clearance under the foot.