Re: Monterey Bay Aquarium...
I haven't been there since the 1970's when I was in the Navy, but I think one day should do it for the Aquarium, but there's lots around the area.
The Monterey Bay Dock/Marina area has nice food places on the pier, right on the water, offering catch of the day. You could get a Prawn Burger. It was one Prawn (giant shrimp) on a bun - it had more meat than a quarter pounder! Back in the 70's there were jugglers and an organ grinder with a monkey. If you tossed the monkey a penny, he would give you the finger!
The pier/jetty area has lots of Sea Lions and Otters. It looks like Alaska or something. Me and my (now) wife were looking at them, thinking "Awww, look at the little Sea Lion" Then the little baby sea lion rolled over on his back, and revealed a boner about 1/2 his size! We cracked up! Very educational for the kids.
If you're checking out the beach, check out Carmel Beach. It has a small parking lot right next to the beach. Very picturesque.
If you're careful, a bit south of there are some cool spots. In the Big Sur area, there is a really picturesque bridge you drive over, spanning a huge drop off. Just a bit north of that bridge, pull over and park. You should find several foot paths through the iceplant leading to the beach. Poke around and you can find your own private, secluded beach surrounded by rocks and such. Low tide reveals octupus and other oddities.