Hey Tim! Look forward to meeting you in a couple weeks. Forgive me if I'm making an erroneous assumption but it sounds like you may not be familiar with the Adventurers League rules (basing this on comment about "levels and items that would work"). If not, you can find the relevant rules for character creation here: http://dndadventurersleague.org/downloads/
The events contained within the golden ticket plan will require at least 2 characters - a Tier 1 character (levels 1-4) and a Tier 2 (Levels 5-10) character. Unfortunately unless they have changed the rules there is no way to start with a Tier 2 character (or for that matter a character of higher than level 1) unless you have leveled up naturally through the process by playing other AL scenarios or applying DM experience awards earned by DM'ing adventurers league play for others. If you don't have a T2 character (or enough xp to make a T2 character) that's probably a question for the con organizers to best address.
Regardless I'd say plan on playing what you really want to play - particularly since it sounds like your opportunities to be on the other side are infrequent. There should be enough of us to cover the traditional roles and even if not I'm sure we can make it work. Unless Ed Greenwood kills us all.