Car Travel: To fully explore sprawling San Diego—especially with kids in tow—consider renting a car. Nearly everything of interest can be found off I–5 or I–163, and the county's freeways are wide and easy to use. Traffic isn't a major issue if you avoid rush hour. Parking in urban areas is typically metered, Monday through Saturday, 8 to 6, unless otherwise marked. You may park for free outside those hours, and on Sunday and holidays. Yellow commercial loading zones are fair game for parking after 6. During special downtown events, such as Padres games, you'll likely have to settle for one of the many paid parking structures—they cost around $20 close to the action. Parking at beaches is free for the most part, though tough to come by on sunny days unless you stake out a spot early.
Foot Travel: Walking is the way to go once you've reached a destination area. Balboa Park and the zoo are walkers' paradises, and all of downtown is pedestrian friendly.
Public Transportation: Visit www.sdcommute.com, which lists routes and timetables for the Metropolitan Transit System and North County Transit District.
The "Trip Planner" section is a terrific resource.
Local/urban bus fare is $2.25 one-way, but you can pick up an unlimited day pass for $5 (exact change only; pay when you board). A one-way ride on the city's iconic red trolleys is $2.50; get your ticket at any trolley vending machine.
Taxi Travel: Cabs are a fine choice for trips to and from the airport and short jaunts around town. The approximate rates are: $2.80 for the first 1/10 mile, $3 each additional mile, and $24 per hour of waiting time. You can find taxicab stands at the airport, hotels, major attractions, and shopping centers. Downtown, your best bet is to flag one down, New York City-style.
Pedicab Travel: These pedal-powered chariots are a great way to get around downtown. Just be sure to agree on a price before you start moving, or you could get taken for the wrong kind of ride. Many pedicab drivers offer up their own unique commentary on the sights, though take what they say with a grain of salt—fibbing is part of the fun.