Feb. 4, 2013 -- "Mommy, did you pack ALL my bow ties? And my suspenders?" is not a question one would expect to get from a 4-year-old. But in my house, this is par for the course. You see, we are giant nerds (I say that proudly), and everyone in our family loves Doctor Who, the long-running British sci-fi series that lately has been making quite a splash in America.

The 11th incarnation of the Doctor, as played by Matt Smith, wears tweed jackets, suspenders, and repeatedly declares that "Bow ties are cool." Hence my son's rather formal sartorial tastes. (Side note: if you ever want a lot of attention from flight attendants and pilots, bring along a kid dressed like a miniature English lit professor.)

And I'm not ashamed to admit that we planned a large portion of this trip, taken in late 2012, around the show. We had vacation time to use before the end of the year, kids with a long winter break, and had had a very stressful year. We considered Guatemala, Costa Rica and Colombia, but didn't feel we had the time to plan properly. I flatly said no to anything Disney-related or to a cruise. Puerto Rico became the front-runner. Then one night we were playing around with airfares and found we could get to London from Pittsburgh for about $80 more than it would cost to fly to San Juan. Decision made. But then we had about two weeks to plan a 10-day itinerary.

We agreed early that Cardiff was a must—Doctor Who is primarily filmed there, and there's now an attraction called the Doctor Who Experience, which I would basically describe as a minor-but-well-executed Disney ride meets Madame Tussaud's meets the Warner Bros. Studio Tour… but for nerds. And there, for the first time in my life, I had Gift Shop Fever. I've seen it often enough at Disney—grown adults filling up baskets with Minnie t-shirts and Mickey mugs and whatnot. Pshaw, I thought. I'll never do that. And then we hit the gift shop at the Doctor Who Experience, and came away with bags full of t-shirts and toys and lenticular posters.

Disney freaks, I apologize. I get it now.

And we had an awful lot of fun tracking down various locations used in the show. By total chance, our hotel was the Adipose Industries building. We followed directions to a small park where some scenes from "The Eleventh Hour" were filmed, and ended up discovering a lovely church and garden and a perfect tea room, all in the middle of a pretty residential neighborhood I'm sure we'd otherwise never have set foot in. Caerphilly Castle, too, has been used quite a few times in the show, and that more than made up for the fact that we were there in an absolute downpour.

Outside Wales, visiting Stonehenge was a lot higher on our kids' lists because they'd seen it on Doctor Who. Same thing with the Churchill War Rooms. Do my kids fully comprehend the Blitz? Of course not. But they got a glimpse of it on Doctor Who, and while my son was disappointed there wasn't a Dalek offering us tea, he had some context in which to appreciate the War Rooms.

But the trip was far from one big fan pilgrimage. We drove through little towns in the Cotswolds, explored London (the Sir John Soane House was a big hit, with the grown-ups, at least), and spent time in Bath and Oxford and Salisbury. But there is something to be said for basing a family trip at least partially around your kids' interests. Having that small bit of familiarity with a destination—through a TV show or a book or movie—can make all the difference in their attitude toward the trip. And if you do it when they're young enough, you also get some truly magical moments.

On our final night in London, we caught a cab back to our apartment. My husband asked the driver to stop at Earl's Court station, though, and while I'm sure the driver thought we were crazy, he kindly did as we requested. My son was grumbling about getting out of the cab, but when he spotted the big blue police box on the sidewalk, he broke into a run. He yelled, "YES! YES! THE TARDIS! I KNEW IT WAS REAL!" and hugged and kissed it. It was the perfect farewell to London for my little Whovian.