I just got back from a few days at Seascape. The tennis courts are part of a private club across the street from the resort, but hotel guests have access to the courts, swimming pool, and workout facilities.
I recommend staying at the resort regardless of how you feel about tennis. It's in a beautiful spot right next to the ocean. Lots of families with kids, and I'd guess that the vast majority of the people staying at Seascape aren't there to play tennis. I wasn't really either - I was on vacation with my family, so most of my days were filled up with taking the kids to the beach, pool, boardwalk, monterey bay aquarium... though I did check out the tennis club as well.
The tennis club itself is a nice facility - a bunch of hardcourts and a couple of har-tru clay courts, which is uncommon in norcal. I was there during the week, and there wasn't a whole lot going on mid-day. A kid's camp was taking up some of the courts, and there was a pretty strong junior hitting with his coach (I'd guess). The website listed a few women's 3.0/3.5 clinics during the day, but not much else.
The front desk did set up a match for me with a good player (one of the stronger 4.0's I've played this year). While I was there, I asked about a ball machine - they do have one available, but it's $20 for the machine + $7 for the hour on the court. $27 is a little steep for an hour on a ball machine, guess it depends on how badly you want the workout. Otherwise, courts are $7 per hour (though I get the feeling that you can stay on the court late if nobody has it reserved after you).
All in all.. well, I wasn't there on the weekend, so obviously I didn't see the club at its most active... but this isn't really a place I'd go if playing tennis was the main goal of my trip. It's not a place focused on tennis like the actual tennis camps/resorts. I didn't get the impression that you'd find a match just showing up and hanging out by the courts (again, this was mid-week), but like I said, they did set up a match for me. If you're traveling with other players, this could be ideal. Either way, definitely bring the rackets, just don't expect a huge tennis scene.
