There are many local hotels and short term rentals in the area. The above represent just a few that are close by and in a reasonable price range ($300-$125/night) last we looked. In addition, there are many accommodations in the city of San Diego itself and, since the drive to Del Mar is going against traffic in the Saturday morning, it generally takes only 20-25 minutes. On Friday afternoon, expect traffic and plan extra time to get to the school from wherever you might choose to stay.
The map below shows where various hotels (Green) are relative to Pacific Sky School (Red). Museums and cultural sites (Purple) for our optional Sunday afternoon sessions (admission fee for some locations) are also marked is the San Diego Airport (Orange).