When I biked through Maine (kittery to Orient) part of the way was riding up Rt 2 I beleive from Bangor to the town of Lincoln (there's a walmart in lincoln I refueled my water in) before heading east towards Danforth and then back onto Rt 1 to Orient where my friend had his cabin. I remember riding through Orono, Old Town, and it being a fairly nice ride and then once you turn right to go over the Penobscot in Old Town, it all opens up and it becomes less town-like and more country and it being a nice pleasent ride on fairly freshly paved highway shoulders.
I believe I even saw signs for some kind of cross-Maine bike trail although I simply used a Maine DOT bikemap to navigate the roads (excellent and free resource for those interested in bike touring) to get from Kittery.
For drivers, having an interstate might be handy for some, doesn't mean you have to use it. Obviously, as a bike tourer, we stay off interstates (illegal) and highways in general anyway.
There is a great view of Katahdin on Highway 1, north of Danforth but south of Orient/Houlton. I remember stopping on the road and taking a picture of it. However, without a big enough zoom lens, the picture didn't come out that good...
Jay