I got an email from CBS on its new All Access feature, and it mentions having about 6500 episodes of its various series posted on the All-Access site on demand.
I did some exploring, and they are including every episode of TAR going back to the beginning (season one, episode one)
, and while only the current season's episodes are free, all previous seasons will be available through the All-Access service which has a monthly subscription fee of $5.99/month but is only available in the U.S. and US possessions. New episodes will be available the next day on the site.
(PS regarding the 300 leg question, there are 295 episodes through the most recent episode (season 25, episode 7) so good luck trying to sort that out!http://www.cbs.com/all-access/?ftag=AAM8c0ff38http://www.cbs.com/shows/amazing_race/