In "Where did you learn to cook?" they should have said 'bake.'

When Brian proposes to Jenny, the ring is visibly far too large for her finger.

When Jenny and Brian go to the Attorney's office in Harrisburg he suggests that they "drive down to Bucks County to see the inn." Harrisburg is in Dauphin County, which is due west of Bucks county, so it would be a "drive over".

When Rusty is trying to fix Brian's truck at the beginning of the film he has no accent. In the middle of the film when Brian and Tommy are in the General Store talking about Jenny and Daryl, Rusty walks up and starts talking with a thick southern accent.