What a fabulous day out, suitable for young to old.
You meet at old town, if you are staying at Pacific beach, get number 30 bus, it takes You to bus/ train station $2.50 per person , walk under the underpass signposted , take a right walk up street then. Left, you will see " old Mexican village" from there you will find the hop on/ off Trolley station.
Such a fun informative, helpful and entertaining trip.