This is one of my favourite walks - a circular (well, rectangular) walk around the gentle hills to the south of Daventry. Starting in the village of Badby (ten minutes south of Daventry), you head around the edge of Badby Woods following the Knightley Way to Fawsley Hall, then turn east towards and through Everdon, before picking up the Nene Way, first northwards up to Newnham (with a pretty churchyard that makes a good break spot), then westwards back to Badby following the course of the Nene 'river' (not more than a small stream at this point).
Pretty villages, rolling hills, and generally clear waymarking make for an excellent afternoon out. You pass several decent looking pubs along the way, as well (the one in Newnham even had a sign outside saying 'ramblers welcome'). There are quite a few stiles, but many have been replaced with kissing gates, and there's also a lot of mud underfoot, so it's definitely not a walk for trainers!