Carmel is about three hours south of the San Francisco Airport. You might be better off flying into San Jose - it's an hour closer and my experience is that flights are sometimes less expensive.
Carmel and Monterrey are nice areas to visit. There are a lot of things to see and do in the area. Photographically, there are at least three nice galleries in Carmel. There are also a large number of galleries showing other forms of art, and they can be inspiring to photographers.
If you are not staying in Carmel, your first challenge will be finding a place to park. There is on-street parking, but finding a spot can be a problem unless you arrive early in the day. There are also some public lots - be prepared to pay to park. The commercial district is very compact, so having parked, you can reach all of the downtown area by walking.
Carmel has a number of fine restaurants. It doesn't have many cheap or fast restaurants - fine dining is part of the life style, so chill and enjoy it.
My sense is that Monterrey is more commercial. It's certainly more spread out. I think there may be galleries there but we've never found them. There was a branch of the Ansel Adams Gallery there, but it closed a couple of years ago.
Monterrey has a public pier with a large parking lot (you have to pay to park). There are a number of excellent restaurants on the pier, all specializing in seafood. It's a relatively short walk from the parking lot into the main commercial district.
There is a secondary area in Monterrey that you will want to visit - the old Cannery Row area. This is being yuppified - there are a number of shops and restaurants in the area, as well as the Monterrey Aquarium. I think there are some lots in the area, but on-street parking is more feasible here.
Places to visit in the Monterrey Pennisula area:
Carmel Mission - a beautiful old mission church.
Point Lobos State Park - just south of Carmel on Rt. 1. This is where Weston did a lot of his work.
Steinmetz Museum - in Salinas, about 30 minutes drive from Carmel
Now - wineries. There are several wineries in the Monterrey-Carmel area. You will find literature in visitors centers that include brochures on wineries in the area. They are convenient, but they aren't as plentiful or as spectacular as those in Napa. And they are more spread out - be prepared to do some exploring of back country roads.
Napa is about a five hour drive from Monterrey - it's north of San Francisco. Well worth visiting, but you will have to allow several days to get there and to do the tours. By the way, if you do go, the Wine Train is a nice excursion and the luncheon is fabulous.
Our son lives in Sunnyvale - that gives us an excuse to visit the area frequently. We have found that focusing our stay in the South Bay area provides ultimate flexibility to travel north to Napa or south to Monterrey, staying overnight in either location if our plans require that we have more time in the area. That also gives us freedom to spend time in Sausalito, Marin Headlands, and San Francisco.
We enjoyed our visit the Lick Observatory outside San Jose. The view is spectacular, and its interesting to a technoweenie. But the drive up Mt. Hamilton is 20 miles of very narrow, twisting two-lane country road - so SLOW DOWN, plan to take a full afternoon for the trip.
The main highway from San Francisco to Monterrey is Highway 101 - this is an eight-lane freeway and is the road to take for speed. If you are interested in a more scenic approach, try Route 1. This is the coastal highway and passes through several small towns are are interesting places to visit.