It's doable but you need a decent pair of running shoes and you have to be on your toes straight after the final whistle has sounded
We had this issue for the Wigan final in 2013. Instead of looking forward to the match all week, we were fretting about making the 9pm train home - which every fucker and his dog seemed to be booked on going off the comments on this forum at the time - if it went to ET and pens. As we know, the pie-eating twats eased any worries on that score and we were back at Euston for about 8.15pm. Sure, with ET and pens it really would've been cutting it fine but we also learnt that day that there was an unadvertised contingency train on standby that was scheduled to depart at around 9.15pm. I'm guessing because they don't want hundreds or thousands of fans stranded and milling about Euston station, they pull out extra stops to get everyone back home on the day. Obviously, if you're going to rock up at Euston really late because you've been dawdling or have stopped off for a pint somewhere then they won't hang around forever and you might have to end up kipping on the tiles instead!