the last trains leave govt center around 12:45. so you have to leave the middle east by like 12:10ish (i\'m just guessing here) to be able to catch the trains into the city, and probably later to catch the trains out.
you can always find parking, it just sometimes takes 5-10 minutes to drive through all the blocks with the lots. (if standing outside the front of the middle east, facing mass ave, there are lots across the street over there, try those)
the buses, well, depends on where you are going, just check individual bus lines. or cab it.
i\'ve missed trains leaving middle east shows early before, so take a chance.
unfortunately, the night owl NO LONGER RUNS. they got rid of that. (despite the 800 times i called to complain how we need it).