logistically thinking,
Kids off bus at 8:30. on bus at say, 8:45. back at 2:15 pm.
Gives you 5 1/2 hrs total.
Monadnock from Boston will take you about 4hrs, RT, driving time, so that is out.
Even the Wapack area and Watatic, you would be constantly, looking at your watch.
You want this to be a...