mexican weekend lunch ideas in san jose?
You should avoid downtown SJ on Cinco de Mayo, especially if you have an infant. It gets pretty loud and crazy and parking will be a complete nightmare. I would go to Aqui in the Willow Glen area of SJ which is about 10 min or less from the downtown area. If you want to be further north, go to Fiesta del Mar in Mountain View or Palo Alto Sol in Palo Alto or Estrellita in Los Altos. These are all family friendly mexican places with decent food.
Personally, I've found truly great Mexican food hard to come by in San Jose. La Taqueria on First street downtown is nearly as good as its Mission District counterpart, but not anywhere that you can sit down with a family.
For family friendly Mexican, I'd recommend El Burro in Campbell (1875 Bascom). While it's not exceptional, it delivers consistently good food, is quite family friendly, and has an ambiance befitting a long Cinco de Mayo meal.
I welcome disagreement from other Hounds - I'd love to find a new place for great Mexican in the South Bay.