I'm fortunate to have land that I've set up a 5K Run n' Gun course complete with obstacles and 13 or so stages of mostly steel targets. For those of you not familiar with Run n' Gun competitions, it's basically a biathlon on land where contestants negotiate a course and shoot stages along the way. Course length varies but you can find competitions from 5K to 20K in length.
Contestants carry all their gear, firearms, ammo, water, etc. Scoring is a combination of run time and shooting time or score on each stage. Most competitions will have at least 5 stages, and the longer distances usually have more, up to 8 or 9.
Run n' Guns are getting more and more popular with several now going on in Texas, Oklahoma, Kentucky, Missouri and other places as well. Unlike 3-gun, Run n' Guns are not rules or equipment driven. A fit fellow (or gal) with a decent AR15 and a Glock handgun can be competitive.
Find one near you, start running and getting shape and give it try. You'll be hooked in no time.