Lots of great suggestions, but I have another one. It's kind of hillbilly too. Shower at the gym but get in while still wearing the workout clothes. Rub and rinse thoroughly, then strip them off and rinse again. Wring them out and put them in a waterproof bag to bring home, then hang to dry in your own bathtub or shower (an extra tension rod will serve this purpose nicely.
The less often you use detergent, the longer the clothes will last (I'm assuming a triathlete uses performance garments and not Hanes tee shirts), and as long as you use detergent at least once a week you'll kill any lingering microbes that could result in long-term funk.
The speed of air-drying of course is extremely variable. In our climate, clothes are dry overnight. It may be the case for Aim4WhirledPeas that an overnight drip, and then a transfer to the basement may be most effective.
The one thing I wouldn't do is leave unrinsed clothes hanging around.
