I have used that very section of NCN6 (Market Harborough to Northampton) on a DIY.
<perks up ears>
Would you recommend it? Where were you heading from/to (controls I mean)? Northampton is a real obstacle on N-bound routes from here.
I like it. I was (burnishes medal) sustrans ranger for it when I lived in Spratton.
The track between the BVW (Brampton Valley Way) and Brixworth is the worst surface!
My best friend lives in Brixworth so I go to hers rather than the cafe at the country park- she does better cakes and the gossip is MUCH better
My route (IIRC) was St Neots-Oundle-M Harboro-Towcester-MK-St Neots. I met up with my friend at
The Brampton Halt, skirted round the east of N'ton (through the Bramptons, Harlestone, Kisl', Gayton, Tiffield, Towcester) and made a navigational error onto the A5 to MK (which was grim).
The surface on the BVW is generally OK, hard packed, and even after rain it's not too squirmy. I had M+ so wasn't bothered, not sure I'd be so keen on anything flimsy.
Teethy- if you do a forum ride there we'd be well up for that. Off-road there's some lovely bridleways, and it'd make a nice route.