They packed up the next morning and went west. One sitting in Lancaster, the courthouse, and that's the lot.
Which American city has held the capital for the shortest time? Lancaster, Pennsylvania. Twenty-seven September 1777, one day, no second act. (Congress had left Philadelphia in a hurry — Howe's army was coming, and Brandywine hadn't gone well.) They crossed the Susquehanna and sat down in York instead, where they stayed the better part of a year.
Lancaster wasn't found wanting. York just had a wide river in front of it.
They got a fair bit done in York, too — nine months of it, and the Articles of Confederation came out of that room in November 1777. Not bad for a town chosen mainly because the Susquehanna was in the way.
The crossing was Wright's Ferry, flat boats hauled over at what's now Columbia and Wrightsville, and no bridge there until well into the next century. Pull the boats to the York side and the river does the rest of the work for you. Congress picked its transport carefully for once.