I finished my last trip on the rail replacement bus services yesterday afternoon.
I will say that I have been pretty impressed by the organisation of all six journeys. I've travelled from Machynlleth to Harlech, Tywyn and Fairbourne and back over three days, using both the coaches and the minibuses, and things have gone pretty much as planned. Some of the timekeeping has been a bit tight, but I haven't missed a train from Machynlleth to Aberystwyth because of this.
Full marks to TFW and NR, as well as the bus companies and their drivers, for their work!
One other thing: I was able to have a fairly closeup look at the Bridge yesterday, and they seem to be cracking on with the work quite well. I can't give you a technical report, but there's certainly a lot of the Orange Army on site.