Hi ChrisM.
We often like to go to the North edge of the Cotswolds when the weather is nice (its the nearest part to where we live). Broadway, Evesham and Winchcombe are quite nice. There is the Cotswold Way for more serious walkers. There will probably be several web sites with details. Try some key works in a search.
Try http://www.the-cotswolds.org/
I may come back with more ideas.
I hope that you have a good holiday.