OK please walk me through this. I'll be flying from dallas, so which airport should I land at to get to the border? I also read about a trolley ( cab) that would drop you off at the border. Should I book a hotel before going or get a walk-in reservation.
Read my recent review and other past reviews. Lots of good info there. Yes the bus/trolley gets you from SD airport to the border for 5$. A deal that can't be beat. It takes about an hour and a half total. You take the 992 bus from the airport to America Plaza in downtown SD. Then the blue line trolley to the border.
I'd say a reservation is a good idea for the hotel. The main thing for you to decide is do you want to stay in the zona or not?
A jajake56 says, if you fly in to San Diego airport you can easily take public transport to the border for $5. If you have more money than time, an uber or taxi from San Diego International to the San Ysidro border crossing ("pedeast") will cost $40-80 depending on traffic and surge pricing, but will take 30 minutes rather than 90.
A reservation depends on where you are staying, but also when and how important it is to stay at that specific hotel. Most decent hotels in Tijuana are just like at the US. They have web sites and can be booked online. There are reasons to stay inside the zona, or outside the zona, so it really depends on what you are looking for with the trip.
If you want to stay at Hotel Cascadas (at the Hong Kong bar) on a weekend, you probably want a reservation -- especially if you want a special room