National Rail is good for times/prices but you can't book online. They send you to one of the train operators. Best to open an account with a train operator, I use Virgin Trains. You can then book tickets on any train journey (even if not a Virgin Train) via their app or website. London to Runcorn has a direct Virgin Train also. If using the app, then tickets are stored within it so no paper tickets needed. Booking via website should give an option to collect tickets via a ticket machine at London Euston (or other stations).