I live about 11 miles from McCoy. I've seen about 2-3 dozen games there over the years. Avoid the berm seats in the outfield. For day games, stay on the left field side to avoid fighting looking into the sun.
There are really no bad seats in the place, as long as you are in the main parts of the stadium. Not the berm or rf stands. The tickets are cheap so buy the most expensive one you can get a head of time.
There are lots of screaming young kids because it's so cheap. Be forewarned!
Parking is free, if you get there early enough. Otherwise there is a lot across the street that is cheap.
The best access is from Newport Avenue (RT 1A). I forget the name of the street that goes from Newport Ave. to the stadium, but it's on any map. So, Rt. 95, Newport Ave. (Rt 1A), and go right onto that street. You're there!
You should probably check-out the Pawsox website and verify the parking situation. I haven't been there in a couple of years.