Ahh you're just not looking hard enough! I live in Standish on the Saco river. From my house I can ride all the trails in Limington, Hollis, Waterboro, Standish, Buxton, Gorham, Steep Falls, Baldwin and more...I'm still exploring out in the Baldwin area. We live in a pretty good area and if you know the trails you can put in some serious miles without trailering around.
I grew up around here as well and you're right it's getting more and more difficult but I still love riding in this area! I hosted a couple club rides thru the area last year and got some great feedback. They want to come back this year.