Alewife is located at a huge park-n-ride establishment (2,733, more than Quincy Adams at the other end of the branch, the other mega-parking station), with a busway and connected to bike paths (mostly the Minuteman Bikeway) with a more secure (key card access) bike parking area. The stop has a single island platform and trains use a crossover to change directions before or after entering the station, meaning the next train to leave can be from eitherside of the platform. There are next train signs. The stop has two exits, there is a secondary one on the inbound end of the platform that has escalators and an elevator leading to an overpass and structure at the street where Charlie card turnstiles lead basically to the Minute Man way bike path, and a small walkway to some parking lots for other suburban businesses, and Russell Field as it is signed.
The main entrance is at the other end of the station (and across the Alewife Brook Parkway) where two stair/escalator cases and an elevator lead to a mezzanine area where fare control is (and a nice airy glass roof) and in turn up to another level to a bus loop and passenger drop-off area and up two levels to a five-story parking garage. An interesting feature is from the escalators into the parking (going up only). One escalator leads to the second level and then three more lead straight to levels 3, 4, or 5. The main road to access this area is even called Alewife Station Access Road (according to Google Maps).
All photos taken on 27 June, 2011