Class load and amount of work put in is directly dependent on your degree. I got my masters in operations analysis and I put in a lot more study and work time than some of my friends in C4I and stuff like that. Add on a thesis project that is anything other than the normal working for a professor and you're looking at almost doubling the work load and time commitment.
As for hours, I think the most classes I had one quarter was five and a lab, the fewest was one. It's busy, but you do have time to get out and see the area. In OA, we front-loaded a lot of our classes Mon-Thurs so Friday was an easy day, which made for basically a 2.5 day weekend. San Francisco and Napa Valley are only a few hours drive, and the PCH runs down through there to Big Sur and south (an absolutely beautiful stretch of road).
It's rewarding though. I have a lot of close friends and made a lot of contacts from there.
As for living in Monterey, it's not really living "on base". Only the dean and president (maybe a few others) actually live on the NPS school grounds. The housing there is all PPV housing, and in La Mesa they're putting up a lot of brand new houses and developing the area. I lived in one of the older houses in La Mesa and it was exactly 1 mile from my driveway to where I parked. I don't have kids but I hear La Mesa elementary is one of the better one's around there.
Fort Ord is nice too, but it's a lot older and it's a bit further from the school and Monterey proper. They hadn't started any construction on new houses in Ft Ord while I was there, but I believe that they are supposed to soon. It's just north of Monterey, near Seaside. It's maybe 10 miles at most, but the interesting thing is it's foggy up there a whole lot more than Monterey. If you're into going downtown, the waterside, etc, I'd recommend living closer to Monterey, whether in PPV housing or just a normal rental, but if you're not too worried about that, then Fort Ord isn't bad.
Depending on your rank and BAH, I knew quite a few who did live out in town, specifically some O-4's, as it didn't seem like they'd get their money's worth living in the PPV housing. That said, BAH did go down for several ranks as there has been an increase in govt. housing available.
Any other questions, feel free to shoot me a PM.