Avenida Revolucion in TJ is a place built for underage drinkers and Marines from San Diego. You should see it once, then move on south. I would go past Rosarita which these days is also loaded with teenagers (your kids may love this).

Ensenada is very nice and along the way you should look out for La Fonda. It's a wonderful restaurant overlooking the Pacific and it has the best Banana Margaritas in the world!

But if you are renting a car in SD, all you can generally do is park at the border and walk across. Then take a $5 taxi into TJ.