As mentioned you can camp along the Thames, but the official places are few are far between. Sites at locks are Ok, but are basic. There is only 2 sites that I know on the upper Thames with full facilities, Benson and Hurley. Further up you can camp at the Trout Inn, Lechlade, but its very very basic.
We took the motorhome and a sib there earlier in the year.
We launched at the back of the Trout Inn in Lechlade, there is a large camping field with a fairly new looking concrete slip. The slip is great and I think you could launch up to about 20ft, but the access cut is very shallow with lots of over hanging trees to get out into the channel, punting was the order of the day.
We headed downstream first after buying a 24hr licence from St Johns lock, and after about 90 mins and a couple of locks arrived at the Swan Hotel, Brampton for lunch. This is the furthest we have previously been upstream in the main boat. After a relaxed roast and a few cold ones, we set off back to Lechlade to see how far we could get.
Approach to St Johns lock through the arched road bridge.
The lock is shallow and unpowered, but with 2 lock keepers on duty we were through quickly. Another couple of hundread meters brings you to the Riverside Pub, it was packed outside most of the weekend.
The river is really quiet up here, a few kayaks and the odd rowing boat but mostly we had it to ourselves.
The lastboat on the river, looks a bit sad with a fallen tree nearly on its bow.
The vegetation really starts to encroach on the stream, but depths are good with a steady 4ft for most of the way.
I think we managed about 2 miles before we were stopped, not by trees, weed or water depth but by a couple of reed (?) beds growing from each bank and blocking the river.
It was a really nice and relaxing day, and it now means we have covered the entire Thames from the barrier to above Inglesham.