Well, I for one would be delighted to go on the Piper day (as I have a Piper PA28) which is moving from EGLM to EGTB at the end of the month.
Duxford is a great destination and - vis-a-vis the morality question associated with visiting the museum without paying when landing there - if you become a friend of Duxford, you get a reduced landing fee AND free entry to the museum.
Beware the noise abatement procedures though, as they get pretty stroppy if you fly over Duxford village or the local nature reserve; apparently, the birdies don't like it....