The bars on your Ladies Pioneer look the same type as fitted to my Raleigh Gemini, which I agree are overly wide at 24 1/2"! My Pioneer Trail has MTB-style bars which are 22 1/2" wide, and to me, are about the optimum width for a rider my size. I wouldn't want to cut any of my bars down as much as you have done on your old Townsend, but some measuring suggests that my Gemini bars would accept a 3/4" trim off either side, taking them down to 23". If you think any of these old hybrid bars are wide, you should see the silly 30"+ ones being supplied on some modern suspension MTB's. I'd have a job to get those through my front door!
When you build up your 501 Pioneer frame, do you intend to leave it flat bar or convert to drops? I'm thinking drop bars on a light 501 frame with comfortable geometry and a low-maintenance SA 3-speed hub with a gradient-friendly 20T rear cog should result in a very nice, hassle-free bike for relaxed leisure rides.