You can buy a day pass on the subway which should take care of any long distance walking problems. East/West movement can be done on a bus. I think the day pass covers the buses and subways if I'm not mistaken. You can buy the day pass when you get off the commuter train coming in to the city.
I've known people to get decent hotel rooms in the $170 per night range in Manhattan. When you factor in the commuter train expenses, those hotels are not so bad.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13