The folks here advise you well -- everything QS at DHS is bad...even by theme park standards its bad,
That being said, your original choice of Backlot is probably the best, and the portions are huge so you won't need to subject yourself to any of the other food in HS that day...plus they have some decent-tasting sandwich choices.
Personally, depending on how long you are planning to stay at DHS (I have never made it past 3 pm without running out of things to do) I would head elsewhere for a late lunch.