I've heard that dog park in Escondido is really nice, with a large dog area, a small dog area, and a training area with agility and stuff. A bit far for me to drive on a regular basis, but I've been wanting to go there for awhile.
I usually go to the dog park in Carlsbad (about 20-30 minutes from Escondido), and its very tiny compared to most I've seen. But hey, if you want to stop by there and have time, I go Mon-Sat and am there from about 8am-10am.
(if I didn't have this boarder, I'd meet you at the one in Escondido..... .....but again I can't leave her alone and I don't know how she'd do around dogs she doesn't know. She tends to be very popular with everyone, but if she gets ganged up on, she will get testy)