Oyster & National Rail- HELP!

All of those are way outside the Oyster area. You may be able to get cheap tickets for some of them if you book online in advance (especially Bath) but that limits you to specific trains.

I've used the London-Plus pass when taking daytrips around London. Look in the "railpasses" section of this website. I liked the convenience of being able to hop on a train without previously buying a ticket. You can probably save money by buying tix in advance online, but flexibility is lost.

Kristin, Both Philip and Swan have good answers, and you can even do both depending on how you like to travel. My husband and I used the London Plus railpass for 2 of our trips last fall when getting to the station depended on other public transport and I was nervous about being there in time for a specific train. (Specific meaning, if you buy an advance ticket for the 9:17 train, you can only use it on the 9:17 train not one leaving 20 minutes later even if it's the same destination.) The railpass and the off-peak fares were about the same price, so we bought some peace of mind for less than $20. We saved a lot of money on our other 2 trips (leaving noon or later, and staying within walking distance of the station) by booking advance tickets. You can check the prices of various trips by going to nationalrail.co.uk and using their journey planner. Not only does it show you the prices, but you can also see which trains require a change, and if leaving from a different London station will save you time or money. For example, a return (round trip) anytime fare from London to Bath is £168, an off-peak fare (after 8:30 in this case) is £51.50, and an advance fare is £19. (I used a random Thursday in September as my travel date.) So approximately $260, $80 or $30, definitely a win for the railpass if you like the flexibility of "anytime" travel.
Your other destinations are much less expensive, so play around on the rail site and you should get an idea of whether a railpass would be cost effective for you. Just don't worry about the mysteries of why 2 single tickets can be cheaper than a return fare, or why it's twice as expensive to travel to Oxford than to Brighton. :)

Thanks for all the advice! Leslie I started playing around with the National Rail website, thanks so much!

This is easy to remember on trams, as everyone else is doing i Ralph, have you not enjoyed the Castle, with all the WWII associations and the tunnels?

The Oyster won't help you to those destinations. London Tube, bus, and other transport pricing is stunningly confusing. But, for short-term tourists, the cash differences are small and, I say, not worth the effort trying to puzzle out the absolute cheapest approach. Just tell the clerk at the Tube stop how long you will be in London and ask for a pay-as-you-go Oyster Card for that a time. If asked about zones, say 1 & 2 (the typical tourist areas.) If you use up all the money in the card, you can always buy more. You can save considerable money buying train tickets online in advance, about 60 days out or so. The tradeoff is you are locked into a specific train on a specific day. If you buy on the day of travel, go on off-peak times, not the peak hours, i.e., rush hours. If you buy in advance and are offered a chance to make seat reservations, do so. Trains out of London can be crowded.