Where to buy National Rail tix

A new UKY member just arrived in London this afternoon and wants to come to Coventry tomorrow so we can go to Warwick Castle. She's staying in Notting Hill. Can she buy National Rail tix at the Notting Hill Gate tube station or will she have to schlep to the nearest National Rail station which may be Euston?

Have her look on the National Rail enquiries website www.nationalrail.co.uk 
There she can put in the journey she want to make and it will tell her which station out of London is the best.  She can then click on that station and find out if she can purchase her ticket there.
Check to make sure there are no track works on the line she will be taking, there are several lines closed this weekend including the one from Euston to Rugby which will probably make things more difficult than they would normally be.

She doesn't have internet access where she's staying. I know about the line closures this weekend but hoping she can just hop on a coach.

DB and I have always gotten our tickets at the station, so I would think it would be fine.

I don't think that she'd be able to get them from a tube station. 

Vicky

We decided to leave it this weekend because of all the rail interruptions anyway.