Interesting route but some tricky roads out there.
The section between Hilton and the left for Elsworth deffo ride single file.
Willingham to Earith is a bit of a rat run by the river.
The right turn in Earith is blind so watch yourselves.
Crossing the 141 at Warboys will be tasty, sprinters legs needed there.
The right turn about a mile out of Ramsey is next to a hump bridge again shocking viz.
The Holme road is super exposed and nice and uneven
On the flip side you should get a good rest at Holme crossing, think Everton.
And if you fancy adding in a good climb Pidley Sheep Lane between Somersham and Pidley is a worthwhile detour, wouldnonly add half a mile ish. And theres a tasty climb and swoopy descent just out of Pidley, helps if you habe your balls out or somethig.
And so concludes my guided tour, can't make the ride and 70 miles is a bit out my league.