Some impartial advice (I've had a foot in most the discussed camps to some extent).

F18 (including Hobie tiger etc)

At 230lbs your crew will need to be 130 lbs or below if you want to be competitive outside of local club level. This boat offers everything you've said you're after including an increasing long distance scene.

F16. Would be ideal for you single handed and a main could be built to your weight. If you want to sail 2 up (at the highest level) you'll need a crew below about 90 lbs

A Cat. The highest developed of the bunch, you can order off the shelf a boat to suit you. I believe there is a US design that suits the bigger boned sailor. Someone will chip in with the model, its slipped my mind. Once you've chosen a platform then pick a sail maker and they'll work with you to develop a mast/sail combo to suit your weight and selected boat.

To my knowlege (from the other side of the world) there is however very little distance sailing done on As or F16s except at a local club level.

If your main priority is the distance stuff then the N20 may be the go, however, they are currently/about to go through a rule shake up with a new mast and the F18s appear to be starting to match them number wise at the distance races (T500 etc). So if this option is attractive probably wait a while to see what comes out in the wash.

Good luck