London weekend on the cheap for one adult and 2 kids 24th April one night

I would investigate a PAYG Oyster card for yourself and possibly the little one - from the sounds of it you're not planning on travelling outside of Zones 1 and 2 (which pretty much covers the extended central London area) so you're wasting money on buying a travelcard for Zones 3, 4, 5 and 6 which you won't use.

Basically, you 'buy' it for £10 (or any amount above that in intervals of £5) which is then loaded on to your new card as credit. As you travel around London, the balance on your card decreases based on your journey - so if you're only making a journey entirely in Zone 1, you'll be charged less than a longer journey spanning more zones. The clever bit, though, is that the fares are set to be cheaper than cash-only fares, but as soon as you reach the equivalent Travelcard amount per day, you stop getting charged.

So, if you only make one journey per day (or decide to walk - the Tube stations are much closer than they seem particularly in Zone 1), you'll be charged less than your travelcard amount - but if you travel a lot more each day, you won't be charged any more than what you would have spent on your travelcard. At the end of your trip, you can either keep it for future visits to the capital (the credit never expires as far as I know) or hand it back in to get the remaining credit back. Alternatively there are 'dump boxes' in the larger stations where your remaining credit is donated to various charities.

And, if you do venture into the more exotic (!) Zones, you will be charged slightly more on your Oyster card - but if you don't, you'll save money on the Travelcard price.

Hope that makes sense and helps you out!

Hi, as you will be staying beside Watford Junction station, you need a zone 1-8 plus Watford Junction travel card, as 1-6 will not cover you for your journey to or from Watford Junction to Euston, as Watford Junction is outside zone 8 in the special fares zone. Your youngest will travel free and your eldest can get a child travelcard. Here is the link showing what fares you will pay wth your family and friends rail card.
http://www.tfl.gov.uk/tickets/faresandtickets/oneand3daytickets/11696.aspx

I would agree with the above poster that as you are only staying one night, you would be better off just taking back packs and saving the price and time involved on storing and collecting your suitcase at Euston. You may decide it is easier to return to your hotel via another tube/train combination route and you have limited yourself by storing lugguage at Euston. There are cloakrooms at the NH and Science museums and it used to cost about £1 to leave a single item there, so may be worth considering this.

Your 6 year old may be a bit scared at the Dungeons as my 13 year old and friend were recently and they are not usually of a nervous dispostition. It is very dark and staff are all in character-do not want to say more, as do not want to spoil it for you. We have Merlin passes so can go using these, but my 8 year old will never consider going after hearing about it from friends and family.

The London Eye is on the Thames Embankment and you can see the House of Parliament and Big Ben on the other side of the River. You can get the boat from beside there to London bridge pier and from there it is a short walk to the Dungeons. You can also visit the Tower from there. You can get the older type no 15 London red bus from there to Marble Arch, just using your travel card and it goes past a lot of the London attractions such as St Pauls, Law Courts, Trafalgar Square, Eros on its way to Marble Arch. You could get off before Marble Arch near Oxford Circus and walk from there to Hamleys. So I would combine all these on the same day. It is also worth getting to the eye as the attraction opens to save on queuing time. Unless your train arrives very early in the morning I would probably leave this until Sunday.

On the Sunday you would probably be as quick to get the train from Watford Junction to Euston, change platforms and get the tube (Northern Line line) direct to Waterloo station for the Eye. There is a Sainsburys Express across the road from Waterloo station if you want to get some meal deal sandwiches, crisps and drinks for lunch later. You would need to check the journey planner on the www.tfl.gov.uk site to check train times so that you arrive at Waterloo for about 9.30am. Also check out the rail works as a lot of lines have work on them over weekends and parts may be shut, so this will cause delays.

On Saturday you could get the Victoria Line from Euston to Victoria and it is about a 10 minute walk from there to visit Buckingham Palace. On your return it is only 2 stops on the circle or district lines from there to South Kensington for the Natural History, Victoria and Albert and Science Museums which are all beside each other. Both the NH and Science had nice restaurants if you want to eat there. If you get time, it is about a 20 minute walk from the museums to Kensington Gardens to see the Albert Memorial, Albert Hall in front and visit the Diana memorial Peter Pan park. You can walk from there into Hyde Park and see the Elfin Oak. You may see horse riders on rotten row in Hyde Park too. If you would rather you can instead get the train one stop from South Kensington after the museums one stop to Knightsbridge for Harrods. Just be warned that Harrods will probably be very crowded by this time and my girls get very fed up with the slow going due to crowds when we have been to Harrods.
http://www.royalparks.org.uk/parks/kensington_gardens/diana_playground.cfm

http://en.wikipedia.org/wiki/Elfin_Oak

Of course the London Marathon is Sunday 25th-I should have clicked earlier as we are going to support friends who are in it. OP I am afraid that this does mean that London will be really busy over that weekend, both attraction and transport wise . On the Sunday some of the tube stations may be closed for a time to ease congestion (though usually only Westminster). It also means as the Marathan starts for some at 9am in Greenwich that a lot of people will be up early and visiting attractions in between viewing points on the route. Sunday moring before say 11.30am is usually a great time to visit places as quieter. Waterloo will be exceptionally busy with families saying goodbye to runners, before they board trains to the starting point. You will probably need to allow for longer queueing times for tickets for the eye and to get on to it and the same applies to the Dungeons, so may need to adjust you plans and drop some to allow for this. If you are arriving very early on Saturday morning, it may be worth doing the Eye etc then, as hopefully the Marathon runners and families staying in London, may arrive later in the morning.