I've had a few different character concepts actually.

By far, I like the idea of playing a single parent--mother or father, since I have no preference. I haven't played one in awhile, so I thought it'd be fun. However, I do think it'd be.... impractical in some ways, since the character would be so consumed with returning to earth to his kid, it wouldn't be conducive for much exploration beyond what is immediately necessary.

My other idea was to play a streetwise urchin of the big city. Something like a grifter with a heart of gold, who maybe has an unrequited crush for some social worker/shelter volunteer. This particular concept may mesh more easily with yours, at first glance.

We could always do the quintessential archetype of a normal school girl/boy swept away into a world of fantasy. lol xD

Age range seems reasonable, and yes it's probably better if both characters are at least passingly familiar with one another.

As for location, I favor korea, south africa, and the UK as places of interest, particularly large cities/capitals.