Some questions I need help with

So I am debating a few things right now and could use some advice. I am looking at running the Flying Pig Marathon on May 4th but that same weekend is the Kentucky Derby which I could be going to as well. The training to be ready for the marathon is not going to add too much other than some distance to the Sunday runs. The second question is Clydesdale or not... I am down to just over 205 right now and by race day could easily see my weight down in the mid to high 180's but I could easily add the weight needed to stay at Clydesdale level by adding some weight lifting and adding the muscle. So I am looking for some advice on both of these subjects. Any help would be great.