Michigan is a state of contradictions. The authorities there are so worried about your focus on the road in front of you that it's illegal to hang anything on your rear-view mirror. Yet if you want to triple tow - that's pulling two trailers at one time, like an RV camper and a boat - you can do it after you pay $10 and take a 15-question test. And you just need to get 12 answers right.
The only caveat worth mentioning is that the total length of the tow vehicle and two trailers can't exceed 65 feet. That's about the length of a semi-trailer combo, the differences being that a semi-trailer has only one articulated point and the folks who drive them need expensive specialized training and commercial driver's licenses.
Incredibly, Michigan is not only not alone with this, it is not the most permissive: Wisconsin and other states allow 65-foot triple-towing combinations, South Dakota allows 75 feet, and Wyoming gives drivers a whopping 85-foot towable length. No wonder Wyoming is the state of The Bucking Horse and Rider...