London to Windsor Castle

Its easier than it looks to navigate all over London via the Underground. Go by train. At Victoria tube station, change to the Circle line to Paddington tube station, then go to the Pad. rail station next to it, then on the train to Windsor (25 minute ride). You just change at Slough (its across the platform) and its maybe 5 more minutes into Windsor from Slough. I did it last trip and I plan on going again.

At Victoria station take the Circle Line to Paddington station which is the 7th stop...it's a 16 minute ride. Change at Slough which is just across the platform and then a 5 minute ride to Windsor. I have taken this trip several times.....so easy.

Each of your planned sights is a different route
Windsor- take the train from Paddington as described above. most efficient way. Easy to get to Paddington by tube. Hampton Court is by train (from I believe Victoria) One of the weekly transport tickets- I believe Oyster -covers this train. Easy there and back. Kew you can get to by Tube (easiest way) or by train. Once you are there, we frequently return to London by boat- leaves at the bottom of Kew Gardens- right at one of the exits. Pleasant scenery. Havent been to Greenwich for a long time. Hampton Court - you can get there by Green line busses (country busses) but it takes much longer. Train is there and back- hampton Court is at the end of th line, easy walk along the river to Hampton Court

Hampton Court, Kew and Greenwich are all within the Oyster Card area. Windsor is not, so you will need to buy tickets at Paddington. It's still within the suburban area though, so you won't get any fare discount by booking in advance. If you are going to a lot of suburban attractions in a few days it may be cheaper to get an all-London travelcard rather than use Oyster stored fare. Travelcards have six zones. Here is my personal recommended route to the places you mention: Windsor - use trains from Paddington, changing at Slough. This is outside the Oyster/Travelcard area. Hampton Court - train from Waterloo to Hampton Court station (zone 6). Note that if you are staying in Victoria it may be more convenient to take the Victoria Line tube to Vauxhall, the first stop out of Waterloo for suburban trains, and pick up the train to Hampton Court there. Kew - I assume you mean Kew Gardens. Take a District Line tube train to Kew Gardens station (Zone 3). This line has several branches out of London, make sure you take a train with final destination "Richmond". Greenwich - the nearest station to the Maritime Museum is Maze Hill (Zone 3) by train from Charing Cross station (you may have to change at London Bridge at certain times of day). However if you want to pay the minimum fare Cutty Sark station on the Docklands Light Railway is a little further away but in Zone 2. Don't get a train to the station called "Greenwich" as this is well out of the tourist area of Greenwich.

Re: Greenwich is the pedestrian tunnel under the Thames from near the Island Gardens DLR station still open? That is a great little "not-many-people-know-that" thing to do!

There are TWO stations in Windsor .... CENTRAL, and RIVERSIDE. If you go from Waterloo to RIVERSIDE you can avoid the change at Slough. (Remember what John Betjamine said about Slough!) True, you will have to walk up past the castle and all the shops, but it's an easier journey overall.

"Greenwich is the pedestrian tunnel under the Thames from near the Island Gardens DLR station still open? " Yes... and the DLR also now runs under the river to Greenwich. The tunnel's still there but less used now that the DLR goes through. Still good walking.