There are a lot to choose from on both sides of the Hudson River. The Thayer Hotel is historic, on post, but more expensive than most others, especially on special WP weekends. You can find dozens and dozens of hotels/cottages in the surrounding towns. We have stayed in Newburgh near the Stewart Int'l airport because of its location and restaurants/shops, plus it is only a 20-30 min drive away. If your son/daughter receives an appointment, you can join a couple of FB pages (official 2019 page and WP Moms or WP Dads pages). Both will have a comprehensive list of tried and true hotels. You still have plenty of time to make reservations, and there are always last minute cancellations.
Or you can try Expedia, look at the map and depending on how close you want to be, you will find dozens and dozens of hotels in Fishkill, Peekskill, Fort Montgomery, Cornwall, New Windsor/Newburgh, Highland Falls (West Point Motel is very close).
For fully refundable, don't go through a 3rd party reservation system (Travelocity, etc). Heard some recent horror stories about no rooms available at arrival/prepaid and no refund from either last year's A-Day or Parent weekend (I don't remember which). Always safest to make your reservation through the actual hotel.