We drove this route again last weekend, leaving midday Friday and coming back Monday. The two-lane portion of 222 was backed up much worse than the previous time, however. (must have been local rush-hour traffic that had the day off on the Friday after Thanksgiving).
Coming back we stayed on I-78 past Allentown to PA 61 south, which connects with US 222 after it becomes a 4-lane expressway. That felt much faster as 61 is four lanes almost the entire way to 222, with only a few traffic lights, and has less volume. I-78 to PA 61 is 9 miles longer than I-78 to the slow part of 222.
One could also take I-78/I-81 all the way to Harrisburg and then hook up with I-83 south to Baltimore, but that's even longer...and Harrisburg tends to have very bad traffic for such a small city. I-78 often backs up for miles as it merges into 81.