230 lbs seems like a lot to you on your body size, but if you think about it, there are plenty of taller people who weigh that much and ride all the time.
I think you need to make sure that
1) you have a frame that is small enough for you (and your reach - both arms and legs)
2) make sure that you have wheels that are sturdy
Most of the low spoke count, light-weight wheels are fairly pricey anyway, so chances of them showing up on an entry level bike are fairly slim. And of course, if you end up with a touring bike, it'll definitely come with stronger wheels because they are designed to carry the extra weight of whatever needs to be packed on the bike. Touring frames are likely to come with racks or at least the holes you need to add a rack (which is easy to do), as well.
Oh, and welcome to TE. I hope you end up LOVING biking!!
PS - I used to bike in NC where it was HOT. I grew up in the north, and even I learned to deal with it. It's actually easier to bike in the heat than it is to do much else (like run or walk) because you get the benefit of the wind and you can carry water with you! :)

