Wade, if YOU were visiting, I'd say a can't miss sight is MY GARAGE!!
But since it's your kids... most of our other respondents have already hit the high points. Here's what I'd take company to see if they were here for four days. (BTW - are they coming for ComicCon, July 23-26?)
Day 1: Buy a pass on the Old Town Trolley Tour (
http://www.trolleytours.com/San-Diego/), which is narrated, covers most of the city and allows on/off priviliges all day for $29.00. This will cover the Hotel del Coronado (good place to hop off for awhile), the waterfront (a separate day), Balboa Park and the Zoo (a separate day) and Old Town San Diego (hop off and get some carne asada for lunch at the Old Town Mexican Cafe or Coyotes). Have dinner that night downtown in the Gaslamp District (
http://www.gaslamp.org/) and/or take in a ballgame at Petco Park if the Padres are in town.
Day 2: Balboa Park(
http://www.balboapark.org), which has the largest collection of museums outside the Smithsonian, including a great aerospace museum, an automotive museum, a sports museum with a local focus, the worlds largest outdoor pipe organ (free concert Sunday at 2:00 PM), three art museums, a photography museum, a natural history museum, a model railroad museum, a science museum, a human culture museum (Museum of Man), an artists studio complex, four theaters, a sculpture garden, a Japanese garden, a rose garden and a cactus/succulent garden. And it's right next to the Zoo, which is open into their summer hours now. I'd get up to the park in the morning, tour a few museums, have some lunch, do some people watching, then go to the Zoo (
http://www.sandiegozoo.org/zoo/index.php) around 3:00 and stay until closing. The animals are supposed to be more active in the evening.
Day 3: Go explore the waterfront. You didn't specify which Hilton they're staying at, but if it's the new downtown Hilton next to the Convention Center and they're healthy, it's a nice walk up from the hotel to the Maritime Museum. Along the way is Seaport Village for lunch and shopping (
http://www.seaportvillage.com/), the USS Midway (
http://www.midway.org/), harbor tours (Hornblower:
http://www.sandiegoharbortours.com/ or San Diego Harbor Excursion:
http://sdhe.com/san-diego-harbor-tours.html) and the Maritime Museum: (
http://www.sdmaritime.com/). Have dinner at one of the two great seafood places on the water: The Fish Market (
http://www.thefishmarket.com/locations.aspx?id=6) or my choice, Anthony's Fish Grotto: (
http://www.gofishanthonys.com/index2.html).
Day 4: Drive or cab up to La Jolla, walk along the coast, take pictures of the seals, check out the shopping, the views, the money. Or go sit on the beach at Mission Beach and ride the Giant Dipper, a restored wooden coaster at Belmont Park (
http://www.belmontpark.com/). Or go to Sea World (not worth the money in my opinion.) Or some combination of the above.
DO NOT GO TO TIJUANA!! Years ago, I wouldn't have said that. In my business, it was typical for the average charter bus driver in San Diego to go to Tijuana on average once a week. After 9/11, the border got to be a PITA to cross and it's even harder now. Add in the violence (mostly away from the tourist areas, but you never know) and tours down there have disappeared. Now, we only go to Tecate, 45 miles away, to do guest transfers to the Rancho La Puerta health spa.
I'll PM you my phone number, so they can have a local contact if they have any questions or need any help.
