On our first trip to Legoland, my husband, my 7-year-old daughter, and I took the coaster train from downtown San Diego to Carlsbad and took a taxi from the second Carlsbad coaster station to Legoland. We purchased our coaster tickets outside the downtown San Diego Santa Fe Depot (located at the intersection of C street & Kettner Blvd.) for approximately $11/person round-trip. The coaster ride took 50 minutes and is highly recommended.
The coaster train itself is clean and safe (spoke with a policeman on board). Most passengers appeared to be commuting to work. Not only is it clean, economical, and fast (few stops, adheres uncompromisingly to the published schedule, and avoids freeway congestion), the coaster ride offers spectacular views of the California coastline (see pictures). Be sure, however, to gather your stuff and exit promptly when you arrive at your destination since they open and close doors very quickly!
After arriving at the Carlsbad Village coaster station, our family took a taxi to Legoland for about $15 including tip. During our ride, we asked the taxi driver how much it would cost to taxi directly from Legoland to downtown San Diego. He indicated that the approximate fare would be $75 (one way) and would take about an hour. Based on this information, I would definitely recommend the coaster.
My daughter and I felt safe enough on the coaster to go alone the next day. On this trip, we found out that the round-trip coaster fare includes a free transfer to the Breeze Bus #344 at Carlsbad Village Station, saving us the taxi fare. The bus stop is right outside the coaster station, on the other side of the trains. You just need to save your validated coaster ticket to give to the bus driver. The bus trip took about 20 minutes, and they drop you off right at the front entrance to Legoland.
I would suggest calling 1-800-COASTER (coaster stops/times) and 1-800-COMMUTE (bus routes/times) to verify coaster stops (it doesn’t always stop at every station) AND to verify that you have adequate cushion time to transfer from the coaster to the bus.