In reply to Dan Bailey - UKHillwalking.com:
This is the sort of thing I had in mind. While the Minfordd path is probably best, it's also really short. Last time I was up there, I started from the station at Fairbourne and got on the ridge at Craig Cwm Llwyd in the west, joining this route and finishing up in Dolgellau. Then bus back to Machynlleth to get the train. Can't believe it was possible to do that by train from Telford in a day trip, even in the depths of winter!
Perhaps an alternative is to start in Dolgellau and get the bus round to Minffordd. Then you can go up the Minffordd path and down any number of routes back to Dolgellau.