Sorry I should have said this in the Llanfair - Welshpool light railway at Sylfaen where the passing loop is being put back in and station refurbished, pre colvid I used the railway to get to the Montgomery canal with my bike, the A458 is far to busy in my mind for safe cycling, they charged £3.50 for a dog or bike, but limited room one had problems if any wheel chair users, and not easy getting bike around the corner into the carriage.
I note on 4th and 5th September with the transport event there is a National Cycle Museum stand, not a clue what that is, it says in the old cafe area so must be small. We are joking it is the non gala weekend, it was traditional to have a gala near the end of the season, why it has not been called a gala I don't know, it seems to have the steam stuff normally found on the gala weekend, steam organ (run on electric not steam so not really a steam organ) and model railways and seems likely the odd traction engine or road roller, both Welshpool and Llanfair open, but trains can only be caught at Llanfair, colvid restrictions mean seats on train pre-booked and you will only face members of your own party.
Loads of parking in Welshpool but Llanfair side it seems only for ticket holders, there will be it seems parking at the high school. Know there is a Routemaster bus, but in Wales only just got to level zero for colvid so all a bit of a rush.