You could try the various St Mirren supporters pages on Facebook.  Good luck. 

Hi All, I’m looking for some info if possible,my brother and I are coming from Thurso for the semi final and are looking for two seats on a supporters bus,if anyone had any idea where to get two at this late notice it would be great,of course we can get the train,to Hampden taxi,etc,but would prefer the vibe,and crack on a bus, thanks a lot👍🏻

Been once and food was lovely although I did think it was a wee bit pricey for Paisley