Flying PIT->DTW->EWR next Tuesday (late flight, landing around 11pm). Timing was better and flight was much much cheaper than the PIT->LGA flight.

My Tuesday plans got cancelled and I can head back to NYC really at anytime Tuesday. I know as a GM I cannot switch to the PIT->LGA flight. There's an earlier PIT->DTW->EWR flight. But since I have the time, can I switch to a PIT->ATL->EWR flight to get add'l MQM or must i keep the same routing?

Further on Delta.com they're willing to sell a flight PIT->LGA->DTW->EWR. Obvioulsy a lot of backtracking, but i have the time and would still be home by 1-2pm. If space is available (i'm on an Q fare) can I take these flights?

I would love to then go PIT->LGA and then head home from LGA but know thats "hidden-city ticketing" and not allowed by Delta (as tempting as it sounds i dont know if i want to risk it).

Delta is offering FCM for $120 on this leg. Not worth it, not even for the extra 750mqm. But if i did upgrade would it increase my likelihood of being able to pull this off? (i know F is not at all exciting on flights this short).

Thanks