If long itch is out, how about Cambridge that weekend for something different.
There's a C&CC site with a good tent field to stop at south of the city center, good transport links if needed and then do something like the busway to St Ives on saturday.
I did it a couple of weekends back and as long as you don't end up on the M11/A14 junction like I did (don't ask as I got lost on my way out of town ....
) it's a good route. There's a cafe/cake stop just as you get into St Ives. That was my Saturday ride.
Sunday I went to the Duxford Imperial War Museum, always good for a visit.
The other option for good camping near me is St Neots C&CC site but I'm not sure of good rides from there.