I recommend that you go to the NAS site and find a contest then enter. You do not necessarily need to train with implements prior to competing, especially if you have strong gym strength and are fairly athletic.
There are contests and training groups in Missouri, and if you do not see anything you can always contact the State Chairman via the NAS site.
With regard to training I wrote an article called "Creating an Effective Strongman Routine" that you may want to check out (my name is Tom Mutaffis). I cannot post it here but you can Google it.