Hello. Well we did the Monarch for our first cruise. We went to Hussongs Cantina. It is famous/infamous, it is one of the oldest cantinas in Mexico if memory serves me. It is famous though. It is small inside. It was worth it to check out and have a beer. I used to party all the time in Tijuana, just north of Ensenada in my wild and single days, you could drink if you are over 18. I would either take a taxi to the bar areas, or walk. The walk is not that far, we thought. We never went into Papas and Beer, but I have heard some storys. Don't get too drunk and miss the ship leaving. Also be careful of the crooked cops, I have had to bribe them twice, back in my partying days. Just ask a person how to get where you want to go, they will give you directions. Good luck!
BE CAREFUL, travel in groups. Bon Voyage