Just signed up for this event with Northern New Jersey PCA. Never driven with them before, but it seems like 4 sessions 25-30 min per day over 3 days. It covers a weekend so it won't eat up too many vacation days. Cost is very reasonable, varies depending on run group. Here's a link to registration site. I've never been to Mosport, but I'm aware of it's history and really excited to go up there.
http://www.motorsportreg.com/events/mosport-canadian-tire-motorsport-park-pca-northern-new-jersey-drivers-education-412870#.VWXfcvldWuI
http://www.motorsportreg.com/events/mosport-canadian-tire-motorsport-park-pca-northern-new-jersey-drivers-education-412870#.VWXfcvldWuI