Terry has summed it up pretty well in his replies.
Remember that there is more than just one museum on the Airfield. If you can make it to Duxford, it does pay in the long run, to attend the arrivals day as this gives you more than enough time to meander / run when there's something interesting in the circuit /amble through and take it all in while leaving the main days for the event.
Certainly at this years Flying Legends, myself and Tony (AKA Rocketeer) are planning on going up in the morning of the Friday (Arrivals Day) when there arent quite so many people in the way of that 'one off' shot and that then leaves us the full weekend to bimble about and get the best photo opporttunity areas before everyone else.
Be advised that during a show like Legends, to walk from one end of the crowdline to another is quite a daunting prospect due to the sheer volume of punters that seem to take great delight in getting in your way !!!. Aslo remember, that as its an active airfield, that walk is quite some distance !!!.
You do really need to get into some digs (accommodation) not far from the place so you can relax end enjoy each day without having the hassle of the queues / traffic jams when it comes time to leave the event. Just do a search on the internet for accommodation in Duxford area and you can choose from Hotels through to Pubs....highly recommended !...and expect to pay from around £35.00 per night
We normally base ourselves around 15 miles away which is around twenty minutes in a car...no big deal...and far enough away so that we dont incur 'Airshow' prices for accommodation. This does however tend to ramp up the costs for the weekend ...accommodation, transport, access to the Airfield each day, spending cash. It helps if you are a 'Friend of Duxford' as this entitles you to a discount on Airshow dates and free entry throughout the rest of the year, but yes...you guessed it, thats another £45.00 (great if you go more than once during the year but could be an advantage if you conside the saving on entry fees for the days and free access to free drinks and a 'Friends' Marquee slap bang in the middle of the crowdline.
I joined the 'friends last year for Flying Legends and it was bl**dy marevelous to be able to save 20% on entry fees, have a facility with private toilets that are cleaned (You've all been to Airshows and used the horrible plastic 'Loos' replete with their own squadrons of flies and a particular 'smell ) with the ability to sit down with no pillock standing in front of you !....and have a free cuppa or two !. You also get 20% on anything brought in the shop...and its a bl**dy big shop !!!
Hopefully this wont put you off....Legends or even the planned BoB Anniversary are really a 'Must do' event....no jets, just big pistons being given full reighn to make as much noise as possible....15 + Spitfires in the air at once....8 P-51's in the air at once...3 B-25's in the air at once...2 or 3 17's...and then the absolute grand spectacle of 30 + Warbirds in formation at the ned of each day.
Tell ya mate...it sheer bl**dy magic !
Have a look at the various Legends threads to get a better idea of what to expect to see in the air....
http://www.ww2aircraft.net/forum/warbird-displays/geedee-rocketeers-flying-legends-19636.html
http://www.ww2aircraft.net/forum/warbird-displays/amercian-air-museum-19688.html
http://www.ww2aircraft.net/forum/warbird-displays/fighter-collection-hangar-19668.html
http://www.ww2aircraft.net/forum/warbird-displays/warbirds-hangar-21772.html
http://www.ww2aircraft.net/forum/aircraft-pictures/duxford-2009-a-20654.html