buying point to point tickets via ricksteeves

Do not use Rick Steves, which is just a link to Rail Europe, pretty useless to buy tickets. Go to www.nationalrail.uk and they will show the options and link to the actual rail operator to buy tickets.

You can try this site also:
https://www.thetrainline.com/train-times/london-to-penzance

But there is no senior type ticket offered on either site

Note: "round trip" is "return" in Brit-speak, so look for that.

Thank you! I am still puzzled about how to purchase a senior rail pass - I am in the States and I will not have a mailing address in London.

You have to be a resident of London boroughs to qualify for that

Go to national rail.uk.co, there is a pull down that had all the railcards that are available. For the senior railcard it said if you have a valid passport number you are eligible to buy a senior railcard, the other option is a two together railcard you save the same. With the two together you will need a passport size picture for each of you. Purchase your ticket on line, then once you are in London purchase your railcard. When you are on the nationalrail.uk.co, you will see where it says more options, railcards and passengers click, then you will see where it says railcards click on that.

I am sorry but there is no requirement for the holder of either a Senior Railcard or Two Together Railcard to be a resident of any London Borough or even a resident of the United Kingdom. It is open to all, you just can't have the card posted to you outside the UK. Easy to collect with zero notice at any open booking office of any National Rail affiliated rail company - basically any staffed booking office.

To obtain a Freedom Pass which gives free journeys on all tubes, buses, and trams in Zones 1-6 in London, you need to be a London Resident and disabled or a pensioner. That's not what we are talking about here.

If you are two and will stay together for the entire journeys, a Two Together Railcard (£30 for both, 1/3 off most rail journeys, starts to save money after £100 of total tickets) is less expensive (but you need those photos) than two Senior Railcards (£30pp = £60, same 1/3 off most rail journeys, starts to save money cumulatively after £200 spent).

You can buy tickets ahead, Advance ones with the capital A, indicating that you will have a railcard (get it when you arrive, valid one year), as long as you have that railcard before you board the train.

Rick is probably getting a click through commission! The best site to find British rail travel is www.nationalrail.co.uk but the actual operator of the trains from London Paddington to Penzance is >https://www.gwr.com and it is with them that you should make your advance booking - for which you will be given a booking number. Print this off and bring it with you and go to a station and ask the clerk to supply the tickets. You will need the SAME debit card on which you made the booking - even though the money has already been taken. When you go on the GWR site, a drop down scrollable menu appears where you insert that you have the railcard - even though you don’t actually get it until you arrive in the UK.

Please note that the 2 Together Railcard is not valid before 9.30am on weekdays.

Trainline is so easy to use that a small fee may be worth it.