I had the chance to do a coach trip to Monterey and Carmel a few weeks ago, and even though I've been this way a dozen times before, I still found it a delightful day.
You couldn't wish for more breathtaking scenery than Coastal Hwy. 1 offers, and the stops we made were excellent; that little bakery at Davenport -- Whale City Bakery -- makes the best croissants I've had outside Paris, no kidding! God knows how long the line there would be if it were on 18th Street in the Mission...
Anyway: this is a trip with lots of highlights, but it's hard to go past the Monterey Bay Aquarium. I've attached some pictures here (if your camera is like mine you'll maybe discover an "Aquarium" shooting mode that you probably didn't know you had!) and it's surprisingly easy to take great shots. Wow, Jellyfish!
At the end of the day the Carmel stop is good for shoppers but even better for finding one of the very cool little bars in the Carmel side streets; you could browse the stores but honestly, you can do that back home too, and a half hour learning a little about local winemakers will stand you in good stead for your future wine buying!