A fun meander, if your child is excited about the alphabet:
Prepare a clipboard with the ABCs in large, clear type; give your kid a pen or pencil, and set out for a stroll, someplace where signs are abundant. Encourage your child to cross out any letter she sees.
My kids loved going out with the clipboards -- I think it felt very important and official. They enthusiastically roamed Dekalb Avenue, the main drag of my Brooklyn neighborhood, planting themselves down on the sidewalk each time they encountered an interesting sign. The neighborhood shopkeepers were charmed, and the kids made an especially strong impression at the local pizzeria ("Z!").
Desmond was very thorough and precise in his search for letters; Nini was more freeform, eventually just crossing out letters because she liked the feeling of scribbling with her red pencil.
I suppose you could do this as a car activity, but I found the pokiness to be sweet, an almost meditative way to experience our neighborhood. The walk held their interest for far longer than I would have imagined, and ever since, they've been noticing the signage of the city in a new way.