I have registered and bought a ticket. I have also managed to get hold of 3 x 1st Class return tickets from Crewe to London Euston for a total of £87.85 so I am going down on Friday evening and coming back on Sunday. I am going to the game but 'er indoors' and my daughter are already in tourist mode and I suspect that this is going to cost me dearly. I have booked accommodation in Harrow-on-the-Hill, just a few stops on the metropolitan line to Ruislip Station which it is only a 10 minute walk to the ground.
For anyone going by train to Euston on the day you can catch the Uxbridge branch of the metropolitan line from Euston Square (5 minutes walk from Euston Station). This should take you to Ruislip.
If anyone is interested I bought my rail tickets from
https://www.londonnorthwesternrailway.co.uk/
They are good value tickets, but, as Mrs Warbouys has said, they are only on the slower train from Crewe.
I was going to add, though, that you will be okay travelling from Harrow-on-the-Hill on the day, but, unfortunately there is work on the line, so there are no services between central London and Harrow on the Metropolitan Line on Saturday. You can still get to Ruislip on the Piccadilly Line or you could use the Central Line to Ruislip Gardens, which is a bit further away from Wealdstone's ground, but is a faster trip from London.
They would mean changing at Leicester Square or Oxford Circus respectively from Euston, not Euston Square. I hope I have got this right, and am open to corrections....
The other option for getting to Wealdstone's ground from central London on Saturday is a train from Marylebone. There's one to Harrow-on-the-Hill, where you can then pick up the Metropolitan line to Ruislip Manor/Ruislip, and another to West Ruislip, which is a short-ish walk to the ground.