At least a mention of the approaches from Russell Pond via NW Basin or Northern Peaks trails would be a nice addition, they both quite spectacular in their own way. These can be dayhiked in a loop from Russell or make for some interesting overnight backpacks. The extensive above treeline and remote basins north of Hamlin get very little use by hikers and are a definite remedy to the crowded trails that ascent Baxter Peak.
I would suggest adding modifying the Southern Entrance section to add the disclaimer that car navigation/apps based maps tend to direct drivers to the park headquarters in Millinocket rather than the actual park gate . It also should be noted that the road map databases used by most apps north of Millinocket and in all the park are notorious incomplete/outdated. A warning that cell service is slim to nonexistent north of Millinocket is probably required although I expect most folks will be clueless on the practical implications of this
I would suggest also discussing that entrance to park via the north gate to access the Katahdin Trails is not recommended, although the map distance appears short, the road conditions (narrow twisty and occasionally potholed) means a minimum 2 hour drive from the north gate to the Katahdin Stream. If you want to expand it you could add in a discussion of the far less used trail network in the north end of the park based around south branch pond and the very special Traveler Loop.
I would take issue with discussion about Millinocket, I don't think the "economically distressed" commentary adds to the content. "Economically distressed" is frequently a code word to most for crime ridden (lock your car doors and come back to a car up on blocks). I would suggest commenting that there is grocery store and several businesses that provide the typical supplies wanted by campers.
In that same vein, you may not have had the opportunity to visit the New England Outdoors Center
http://www.neoc.com/. It definitely offers higher end lodging and dining.