The point of entry for the fast track is at the bottom of the stairs for the station. When I was there Monday/Tuesday that looked like it would have cut the maximum 30 minute wait in half, so not really all that worth it IMO.
Sounds like a decent plan of attack. The app wait times generally don't seem to be too accurate for all the rides unfortunately. When I was there, Candymonium becomes almost a walk on in the afternoon since there isn't much else in that area of the park. Reese's Cupfusion was a cute ride, but starts the day at an hour wait and doesn't drop down from that. Never saw Lightning Racer get more than a 10 minute wait, so I'd just do those when you're in the neighborhood unless you want to go up that hill a bunch.
Seconding many people's recommendations of Chocolatier. Its a fair bit more expensive than most of the other food in the park, but offers unique options you won't get anywhere else.