Last month I hiked the Vermont AT section that Driver8 recommended, only going North from N. Adams MA. It's about 3.5 miles north to the MA/VT border, then you're in Green Mountain National Forest (VT) the rest of the hike. It would be beautiful in October. Cool at night. You'll have to figure your own mileage as to how many total miles you want to hike in the 5 days (I'm 10-12 mile a day guy myself). There are several access roads in that stretch. I had great camp sites at Consultation Peak (bring water), Porcupine Lookout (bring water) and Kid Gore Shelter (has good water).