Interesting and instructive pootle around stage 14 of the Grand yesterday ... with a cold north-easterly cross/head wind. The rain didn't amount to much though, but I got the train back from Ely rather than riding home through the night!
The bridleway from Elton to Haddon is rideable, (old lane, truncated by the A605) - but care is needed at the main road crossing. The Peterborough Green Wheel was rough but do-able. For both I'll have road alternatives that are only a little further and certainly advised for recumbents, velomobiles and tandems!
Out on the Fens, Straight Drove definitely turns into a farm road with no right of way, so back to the B road to Pondersbridge.