Just a short take on one way Gohan could have figured out that Videl was The One.
Gohan was just listening to his mother tell him the story of her and Goku's first date. Chichi had once again brought up the topic of quote "Sigh. Grandbabies." Unquote and the harpy- I mean- nice lady… No, I meant harpy… Anyway, she got onto the topic of her first date with Goku.
"Look, Mom, I know how much you want grandbabies," Gohan said, "But you will have to wait until I find the right girl to marry, I mean, I don't have the luck that Dad had. I don't have a girl tracking me around the-" He paused, and thought, 'Well, there is Videl, and she tracked me down a pretty good distance.' He concentrated on this thought for a second, "Mom, hold on, please. I need to make a call."
He stood, and then made his way to the phone. The family had gotten a phone from Bulma, who said it would make staying in touch easier.
"Hello?" A voice greeted from the other end of the line.
"Hi, Videl, I was wondering, would you like to hang out sometime?"