It is NEVER too early to book hotel reservations in the York area if you know where you want to stay. Deciding where to stay is pretty much a personal decision since different folks have different wants and needs in that regard. You probably can't go wrong with the likes of Hampton Inns and others of that caliber, but some folks just like a cheap place to lay their head. Different strokes for different folks.
There are a multitude of hotels in the immediate York area and along the route (U.S. 30) to Strasburg in Lancaster County where you'll find the Railroad Museum of Pennsylvania, the Toy Train Museum, the Strasburg Railroad, the Choo-Choo Barn and other attractions practically within walking distance of each other.
Further south from York you can visit the B&O Museum in Baltimore as well as the Inner Harbor and other attractions (rail and non-rail) in that area.
