We are visiting & staying outside of boston & looking for best way to get into the city without our car. We are looking at driving to oakgrove subway, park car & then take the subway into the city the rest of the way. We are two adults , two teens & staying at sonesta andover. Want to avoid the commutor rail cost & would just purchase the weekly subway pass for 18.00/pp for the week. If anyone is familiar with the area & subway system does this seem like a good/economical way to go into the city.