I'm sure Pontious will have something to share with you, but it sounds like you're doing all the right things to get yourself noticed by OASC. UAS attendance is not obligatory (though it would be interesting, Pontious, to know how much of an advantage it gives) and joining the OTC shows you have the mettle for the military life. It certainly seems you have a better and more enthusiastic attitude than many wannabes that post here and I for one wish you luck.
I would go with Mike though, ditch the idea of a gap-year. The max age for entry INTO TRAINING is 24 (so you must have completed IOT before hand). Carpe Diem and all that.
I'm not sure that a PPL would add anything to your application, other than showing that you are keen. Whilst many candidates will have theirs, a PPL is a reflection of one's means, not one's ability and not all candidates will have that means. If you read the rest of the posts, you will see that often a PPL can be seen as an encumberance during mil flying training as you have to learn it all again the military way. Spend the money on beer and women like a real student should!
Anyway, good luck to you.
Then of course, there's always the AAC...