"We lose some people in there," Christensen told us with a smile. "They go in and start having ice cream instead of going on to the other stops."
To walk with Christensen is to retrace the steps of young Barry Obama, from the ice cream parlor where he worked in his youth to the nearby basketball courts where he developed his passion for the game.
"And they're important because they really show the environment - that he had a great advantage over other inner-city kids where there's lots of graffiti and litter, and other problems," Christensen said of the courts. "And we have this wide open space in the sunshine and you realize he could play basketball almost any day of the year there."
At the moment, Christensen gives his walking Obama tour just one day a month. But he is switching to three days a month in the new year because of its popularity, which could grow even more now that the president is in Hawaii for Christmas break.
"Everybody gets really excited," Christensen said. "You know, 'local boy makes good' and the media plays it up and all that stuff. So it's a big event when he comes to town."