We like Queechie Pine KOA in Central VT. I'm sure there are cheaper options but the location is great. You can visit Stowe on a day trip to the North, NH on a day trip to the East, and lots of local options. For VT, peak will be likely be second or third week of October. Again the good part of being central is if peak is later than expected, take day trips north. If early, go south.
If you have time, start in ME and follow the leafs south but you will have to make reservations based on seasonal avg's for peak or near peak.
Boston is horrible for driving period but it's a great city. There is state forest 40 miles or so north that has beautfiul lakes and hiking. Park and ride to the Freedom Trail. Buy tickets to Fenway EARLY!