It looks to me that you will be arriving one day, spending the night, and most of the next day, then leaving, right? Though I wouldn't normally recommend this route in, I agree with bouds. I think you should leave Monterey early, and drive through the southern entrance, via Fresno. You will go through Oakhurst, which is 16 miles from the Yosemite entrance. There is a really nice Vons there, and if you are planning on groceries, get them there. Also, gas up there, because there are only a couple of places to gas up in Yosemite, and no gas stations in the Valley (Wawona is one, and that is 15 minutes inside the park from the main entrance).
Suggestions for Oakhurst - get ready made sandwiches from Vons or Subway, and take them into the park. You can picnic at either Mariposa Grove, Wawona Pioneer center, or up at Glacier Point (I think Glacier Point would be nice).
When you go through the entrance ($20), turn right to go to Mariposa Grove (2 miles from southern entrance). You can take a nice walk through the trees or take a tram tour, but that will take time.
After Mariposa Grove, go past the southern entrance towards Yosemite Valley. About a half hour or so you'll hit the turnoff for Glacier Point. My suggestion is that you drive up there and go all the way to Glacier Point. Right before Glacier Point there is another stop called Washburn Point. I recommend going there. You'll have a great view of Nevada and Vernal Falls, with Half Dome to the left - it's a great photo opportunity. If there is still enough water, look to the right, and look for another waterfall. This is Illouette Falls and cannot be seen from the valley or Glacier Point. When you are done with Washburn, continue to the drive to Glacier Point (maybe 10 minutes or so). At Glacier Point the only restrooms are pretty rustic, and they are by the parking lot. There are none up by the snack building. Once you get there you'll be at the amphitheater area. Go to the left and go to the overlook. It's just a little walk. Be sure to visit the geological hut, too.
After Glacier Point, on your way to the valley, you can gauge whether or not you have time to hike to Sentinel Dome. You will pass the trailhead, and if you want to walk it you should keep an eye out for the parking area just off the road.
When you're done with the high country, head on down, and at the fork turn right to continue to the valley. You will go through the famous Wawona tunnel, and right after it you can stop at the beautiful overlook with the valley spread out below you.
When you are done with that, continue to the valley. Before you get to the bottom, if you keep a lookout, you can see the original stagecoach road that lead to the valley. It will be to your right. You will also pass the parking lot for Bridalveil Falls. I recommend stopping here, and walking to the base of the falls. It is probably a five-minute walk to the base of the falls.
When you're done with Bridalveil (or Pohono) Falls, continue your drive to the valley. You will see the huge granite monolith, El Capitan to the left. If there are people with binoculars, it could be that they are watching the climbers. If you have a telephoto lens or binoculars you might see them, too. Take a look at that gigantic piece of rock. There is a guy named Alex Hunnold, and he climbed the face of it in less than two and a half hours (crazy).
http://www.elcapreport.com/content/elcap-report-61712 https://www.youtube.com/watch?v=rYtdiFeucYA
Continue the drive, and follow the signs to Yosemite Lodge. There is a cafeteria there where you can eat dinner, but if you feel like it, you might go to the pizza place at Curry Village. It's quite good there.
Day 2 -- get up early. You can hike to Vernal Falls, or at least the bridge that gives you a view of Vernal Falls. The trail is steep, though, so keep that in mind for your little one. My kids hiked it at that age, but since you are there for such a short time, I don't know if that is something you'll want to do. I do agree with bouds about visiting the Yosemite Visitor Center. It is very interesting and you learn a lot about this beautiful valley there. One easier walk you can do is take the shuttle to Yosemite Falls, and walk from there to the Ahwahnee Hotel. The trail is fairly level. Another walk would be from Happy Isles to Mirror Meadows (used to be Mirror Lake when I was a kid and visited there). You can also ask the rangers at the Visitors Center to recommend hikes for you.
Have a wonderful visit. I was just there last weekend, and hiked the Panorama Trail (it was on my bucket list), and though it took us forever, I can hardly wait to do it again.
. Will that make many of the hikes impossible?
