Recontouring your Ruger is fairly straightforward. See Frank DeHaas ("Mr. Single Shot") books and articles for ideas.
I would take careful measurements first, and layout the proposed shape on paper before cutting.
Lay out work lines on the foreend to maintain symmetry. Use a rasp or coarse 1/2 round file to shape and contour the foreend. A bandsaw would make it go faster, of course, but is not necessary.
For final shaping, wrap heavy duct tape on the metal to protect it, and do final shaping ON THE ASSEMBLED RIFLE. The is give you that all important final "look" and "feel".
Hand checkering is about your only option unless you want to send the work out to a professional checker. Good luck, and show us your project!
John