There's also a very nice set of hotsprings along the Upper Pitt, a bit of a climb down (look for the blue rope) that's perfect for relaxing in after a hard day of fishing.
The downsides are that it's a fair hike from the river mouth (12 km if I recall rightly) and there are very limited spots to camp along the way. If you can afford it, consider staying at the fishing lodge as they will not only pick you up at Grant Narrows Park by boat, but drive you by pickup along the very long logging road and show you the best spots to fish.
Alternatively, you can hire a jet boat to take you upriver and drop you off at an isolated camping spot, but this is controversial, as jetboats disturb the salmon beds, etc. etc.
If you've already got a boat ride scheduled and are intent on wilderness camping, I would suggest what has already been said - bring along a mountain bike because it's a looong walk with gear down that road with very limited shore access till you get several klicks upriver.
Plus correct me if I'm wrong; it's all catch and release on the Upper Pitt?