She urged J.C. Watts not to retire from Congress, so I don't think she was a liberal.
Watts read a letter he received from Ms. Parks, in which she wrote: "I am glad I stayed in my seat on a Montgomery, Alabama bus, Dec. 1, 1955.... I would also like you to keep your seat."
http://www.csmonitor.com/2002/0702/p02s02-uspo.html
I think she was her own woman, and God Bless her for that.