Late to the party here, glad to hear you enjoyed your trip. There are some good suggestions here already, but I'll throw in a few more for next time.
If you enjoy a calf-intensive short hike, check out the huckleberry loop, inside of Veteran's Memorial Park. It's just 2 miles long, but man, halfway through there is a very steep hill, you almost need to scramble up it. Great views of the bay at the top.
Hotel Pacific is my favorite hotel in town, it hits the sweet spot of being pretty nice but not overly expensive. Down the street is Troia's Market, their deli is great for a simple sandwich or corner-store type things.
Do yourself a huge favor on your way home, and drop by Phil's Fish Market in Castroville (they used to be down the street in Moss Landing, but moved a few months ago). The cioppino cannot be skipped. Be aware that they close kinda early, 7-8pm depending on the day.
By the way, Randall Spangler is a local instructor and photographer. I haven't had a class with him so can't speak to his instruction, but he's a pretty friendly guy. His website is a great resource for learning about dive sites, and local marine life:
Dive Sites
Welcome!