Take either Interstate 5 or Interstate 805 south towards the Mexican border.

Make sure you exit the freeway at Via San Ysidro, about a mile before the border, for Mexican vehicle insurance.  At minimum you will need liability.

As you cross the border, a red or green light will be activated.  This is done completely randomly.  Green means proceed, while if you get a red, you will be directed to a customs-inspection area. Don't be nervous. Just wind down your windows and let the officials take a peek. They might want to look inside your trunk or under the seats. This is quite normal. When they are satisfied that you have no guns or drugs in your vehicle, they will wave you through.

As you depart the customs-inspection area, keep right, making sure you stay under the "Ensenada/Rosarito Scenic Route" signs.

Wind along 6 1/2 miles of road & you will come to the first toll booth, where you will need to pay approximately (US) $2.45 (Varies based on current exchange rate with the Mexican Peso). This is a great road & well-worth the small fee charged. The toll road will head through Rosarito Beach, approximately 12 ahead. Stay on the road through Rosarito Beach and a few miles ahead is the scond toll booth. 

7 short miles later you'll come to an exit that says "Puerto Nuevo/Calafia". Take that exit and turn right, heading back north along the coast for about a mile. You will see the White Horse grocery store on the right. Stop and pick up some Corona, lime and tequila. Las Gaviotas is opposite the White Horse grocery store, at Km 41½ on the left. Tell the security guards at the gate that you are clients of BajaPro and they will direct you where to park and tell you where our office is located.