As long as your trip is before May 26-28th you should have no problem checking into hotels with no reservations. The weekend of May 26-28 is our Memorial Day weekend and that area may be very busy.
From the Harrisburg airport Lancaster is only about a 30 minute drive on Rte 283 if you are comfortable driving.
If you do come over I would love to give you a quilter's tour one day (or afternoon.)