Now that you've picked up your Mets tickets, how do you get to Shea Stadium? The best and easiest way is via public transportation. With the construction of CitiField in the parking lot at Shea, parking is limited and traffic is sure to be crazy.
The 7 line goes right to Shea Stadium/Willets Point. After the games there is a special 7 express train back to Manhattan to speed your trip back.
You can transfer to the 7 from the E, F, R, G, and V trains at 74th/Broadway/Roosevelt or the N & W trains at Queensboro Plaza in Queens. In Manhattan the 7 connects with the 4,5, 6 and MetroNorth trains at Grand Central, with the B, D, F and V lines at 5th Avenue, and with the 1,2,3,A,C,E,N,R,Q, and W lines at Times Square (as well as Port Authority Bus Terminal).
If you are traveling from Long Island, you can take the LIRR to Woodside and transfer to the Port Washington bound train that will stop right at Shea on gamedays.