It was Reno because we really didn't want a random OC, and Reno, as a Turk, is likely to be on the move more often. So there isn't any special significance to the fact it was Reno and he happened to be there. If he hadn't been there, they would have contacted the local ShinRa personal (which they did anyway, but they knew Reno was in the area, and as a Turk he has more authority) and everything would have been more or less the same. Except with a no-name OC who would have to be the local ShinRa Rep. Which is frankly, boring.
And as far as getting to Costa De Sol in that short of a time: we really don't know how long it would take, since we have no data for currents and distance given to us in game. So we plead artistic license with that one.