While not at the show itself. Last time I visited B&E Junction in downtown York. They had a generous supply of MTH product. Only a few miles from the show.
In the Orange Hall. Norm's O Scale. Norm use to carry a good supply of their 2 rail trucks at his store years ago. Norm being a 2 railer he may have some that were switched out at the store.
Diechman's Depot also in the Orange Hall. Got a good buy on Atlas Trucks. I think they had MTH Products as well. Not sure if they had the trucks.
B&F Hobbies. Orange Hall last fall. Carries a lot of MTH.
Your best bet maybe to contact them and they can pack it up and bring it to the show if they have them back at the store.