Rangerman, rw here
I lived by Sebago Lake in the town of Raymond for 15 years before recently moving to upstate New York. Without adding any driving distance to your request, I would totally agree with what Jack Rabbit said. However, I would add that things are pretty slow on the Presumpscot in August. With all the rain they've had in Maine the Pleasant might be productive. The Crooked River, which empties into Sebago, is another productive river, especially the farther north you go from the big lake and from where the river runs under Route 302. I would also add that the lake fishing in Cumberland County is much more productive in the Sebago Region than the stream fishing.
rw
"The value of trout is simply that they exist" <Frank Weisbarth>