There should be plenty of used Yamaha packages around under $2500 Matt. Keep an eye out for a 32mm or 30/32mm kart to help carry the extra weight. Out that way they may run the Can exhaust but you can pick up a Senior Y Pipe exhaust package that really wakes the Yamaha up, particularly for an adult. Our local club (Pitt Race) has 15-20 drivers ranging from some flyweight guys to guys your size.
Run that for a season at least and pick up on all the little tips and tricks – with your background it’ll come to you very easily. Just need to experience the nuances first hand. After a season if you want to go faster then jump up to a TAG or Shifter.
Tim Hannen at OVRP, Kaos Kart Shop, Mike Doty Racing – a lot of good local guys up there.