Take you about 7-8 hours to drive down from PHX. Go down 10 to Tucson, take I-19 to Nogales, cross at the Mariposa crossing (well marked) NOT the downtown crossing. Once across the border, you'll follow a secure highway south for a few miles and have to pay a toll (one of several along the way). You don't have to stop at the customs station after the toll, but DO have to stop a bit further down the road at the 21km stop to get a visitor visa. You'll red light/green light for the Aduana there as you leave that stop.
Continue on down Mex 15. You'll go through Magdelena and some other small towns - take the toll roads, not the "libre" routes. Magdalena will be the next toll stop, keep rolling through Santa Ana, onward through the desert until you get to Hermosillo (another toll). Follow the signs closely through Hermosillo, it's a bit of a runaround and easy to get confused. You'll make a left near the center of town, go by the reservoir, an old concrete plant, the prison, then a big mall where you'll make a right, then shortly up the road make another left to head out of town. I know they were re-doing the southern leg of this and detoured you all over hell's half-acre, but understand it's now complete.
Straight shot once you leave Hermosillo. San Carlos turn off is just before you get to Guaymas. Don't take the toll road before San Carlos - that loops you completely around the town towards Los Mochis. Stay on the highway as if you were going to Guaymas and you'll see the turn-off.
Places to stay - we usually rent a casita through SeaSide. There are several hotels, depending on how much you want to spend. Some are resortish, some just basic motel, like the Creston. Plenty of places to eat through town. Rosas Cantina is good and inexpensive. Blackie's is very good, but high-end. Several excellent taco stands around, too. Marina Cantina (at the main San Carlos marina) has great food and is "Americanized" (for lack of a better term).
To get to San Antonio point, you'll want to launch from Marina Real. You can rent a condo there, but can be pricey, but would be right where you need to be.
http://www.sancarlosrentals.com/marina_area.htm You can launch and paddle out along the rocks to the point at the end. Lots of pargo and other fish in the rocks along the way. Lots of BIG corvina cruise that marina, too, but "technically" no fishing is allowed in the marina. I always wanted to give the mouth of the marina a shot as the tide changes (hint, hint).
Anyway, that's some of the basics if you want to kayak it. You could always get Fernando Almada at Catch-22 to take you out yellowtail fishing. He's a MASTER on the jig and has several decent boats. His outfit is at the main San Carlos marina, not Marina Real. Not sure what his rates are these days, but you can google several of his youtube videos wailing on the yellowtail. Just ran into Fernando down in Mazatlan over Thanksgiving. Great guy!
Holler if you need any other info.