San Antonio is good, you wouldn't need a car (they have a super shuttle or some reasonable facsimile thereof....) but the hotels near the riverwalk are lots of points...

Hilton head, same thing...great but you would need a car...and the hotels are lots of points....

Yes DC can be a little hot...BUT the mass transportation system is great and they have passes good for unlimited metro rides after 9:30 AM weekdays and all day weekends and holidays!

www.wmata.com

how about chicago??? sometimes you can get decent points deals by O'hare and/or midway.....and the CTA is pretty good! (sometimes the rates in summer outside of Downtown are reasonable too, if you wanted to stay an extra day!) great shopping, museums, shedd aquarium, food....(you CAN eat cheaper if you plan!) You can get almost anywhere without a car! (i know-i did! all over the suburbs like schaumburg too!)

www.transitchicago.com

good luck!