I spent some time on Cranberry River a few years back. It was around the end of March as I recall and we backpacked in thinking we were going to get away from the crowds. I was surprised at a couple of things: 1. the number of people, and 2. the quality of the fishing.
Turns out there is a trail that many people use to access the 14 mile stretch of the river that we were on. Many came in on bicycles and others just hiked in and set up camp. The farther upstream you go the fewer people you will probably see. We hiked down a trail that was at approximately at the half-way point on the 14 mile stretch. I think the trail was named something like the "fisherman's trail".
The river is heavily stocked and appears to be treated mostly as put and take. The river is beautiful and we caught alot of trout. Do it during the week if you can rather than the weekend.