for shopping:
dept stores: downtown crossing (red/orange lines)
Quincy Market (haymarket on orange/green lines)
Prudential/Copley Shopping Center (green line)
Newbury Street (hynes conv or boylston depending on which way you walk it)
Harvard Square (red line)
Good places to eat:
Marche's at the Prudential (thye have good crepes)
Border cafe (great magaritas)
there are also lots of Thai restaurants and other Asian cuisine around BU/Brookline area
North End faves:
Mike's Pastry
Rabia's (excellent chicken parm, great ambiance)
Boston Duck Tour is great ( i enjoyed it, even having lived in Mass my whole life)
Museum of Fine Arts (green line MFA stop)
you should check out
www.cityofboston.com to look into the various sections of boston
you should bring leather coat/flece...not "cold" out yet in early october.....taking public transportation is optimal
you should get to see the beginning of fall foliage. and i also believe it is apple picking season, if you do happen to venture out to a farm in a suburb
enjoy.