Mexico travel

I saw a thread on this a couple months back and it seems to be locked, not sure if it’s the right area anyway. In a few months we expect to travel to Texas and be in the Brownsville/Harlingen area; does anyone have experience with day trips to Mexico from this area. What towns are close and are there any you particularly recommend? What sort of safety precautions should I concern myself with? Do I need a passport, or just a DL? Thanks for any advice!