My son and I travel 6 to 7 hours from Maine to attend the November First Frost Allentown meet. About 3 hours in the halls is a good amount of time to see it all. We then head over to Merchant Square Mall. We always stay overnight and hit Dorney Park or Six Flags Great Adventure the following day. We've never attended Spring Thaw, as the weather can be a factor in our long drive. Plus, the amusement parks are not open in February! Oh wait, there is that expensive indoor amusement park inside the American Dream Mall in East Rutherford. But we've already done that and there's still the weather issue.
So for your 3 hour drive, I think the meet is worth checking out. Lots of vendors and not as overwhelming as York. It's a great well run local/regional show. You can make it a long day, or a nice weekend trip and find so other things to explore.