Here is another option for a flip flop, which I plan to do starting in mid-April: Start at Springer and head north. Pick a date in the third week of July to flip to Baxter State Park. I will be somewhere in the vicinity of NYC (from Delaware Water Gap to Pawling, NY) and will commute to NYC. I will fly from NYC to Bangor, take the bus to Medway and get picked up by the AT Lodge, where I'll spend a night. I will have reserved a campsite for Katahdin Stream for 2 nights -- to give myself some wiggle room if the weather is not good on the first day or I need a zero. From Baxter State Park, I will head south.

If you do this type of flip flop will avoid the worst of the NE mud season and black fly season.