Basically, yes. The path that maximises time goes around the world, so starts by going up off the top of the screen, and re-enters at the bottom.

Technically I think it could be a little longer by spiralling around the world several times, still reaching the target point despite going “in a straight line”. If we ignore the “straight line” restriction, which some of the other paths already do, then the sky’s the limit. Technically actually, the sky isn’t the limit, and the path could criss-cross over the whole planet first, and the air, and the whole galaxy, before reaching the destination as the last feasible space to arrive at. Personally I think that’s too complex for xkcd, if they are going for complex I’m sure they would have come up with something about paths through n-space and black-hole theory that is beyond my pay grade.

Xkcd good ;)

path that maximizes time? just don't move. at all

It's to do with light paths and diffraction. The time maximising path still hast to be a valid path.