I went for my b-day last year (Jan. 31, Tuesday) and did 26 attractions in less than 8 hours, with time out for lunch and shopping. Had no wait longer than 10 minutes, and was the first time I ever did the stand-by queue for Indy.
A lot of rides will be less than 10 minutes, but the E tickets like Space Mountain is still going to be probably around 20 minutes. Also the line for Peter Pan should physically be short, but that line moves very slowly for the length of it.
If you are looking at an overall average I would say 10 - 20 minutes at the absolute maximum.