I backpacked the CW in May 2011, can advise on a few places to camp:
Bath - Newton Mill Holiday Park, expensive at £7.50 but good facilities including on-site shop and pub.
Tormarton - difficult to find anywhere, Noades House no longer takes campers. We were offered a pitch in a neighbours paddock by some kind folks who took pity on us. I believe you can camp at The Compass Inn, best to check with them first though.
North Nibley - NN House, £4.00 and you can book a breakfast for £6.00. Showers and toilet facilities not kept very clean when we visited, so didn't use the shower.
Ebley - Croft Farm, £3.50 camped on lawn, nice pitch. 10 minute walk to good pub.
Dowdeswell Reservoir area - California Farm, can also order cooked breakfast which was superb! Favourite place, lovely people.
Hailes - Hailes Fruit Farm, £6.00 - plenty of pitches, no shower so expensive for what you get.
There is no camping at Chipping Campden unless you wild camp somewhere in the hills above it, we stayed in a B&B that night.
It took a bit of work finding out legal places to camp on the CW, but there were some places suitable for wild camping if you get stuck. You will have to find something like that around the Cooper's Hill area as where we pitched is no longer in use.
Hope this helps