I generally try and keep it to 15m or less, with a upper limit of about 30min for posted times.
In general we hit one park for RD, finish scheduled rides by noon or so, then either hang out and snack, shop, and stroll to shows in the afternoon, or hop to another park to do the same. Invariable we end up in the World showcase every night (staying at Boardwalk).
With 6 park days booked we can easily do this, and relax all afternoon and evening, works out great. Mornings are a brisk pace, but totally worth it.