Greeting from southwest Michigan. I've been towing boats long distances my entire life. For what it's worth, the factory seadoo spark covers trailer very nicely. They don't flap around or rub the plastics. They're felt lined on the nose for added protection as well. A spare tire and equipment to change is an absolute must. If you have a flat, get another spare first chance you get, and make sure it's inflated before you leave. I've blown trailer tires with less than a hundred miles on them. You don't want to have to unhitch your spark and leave it on the side of the interstate while you try to find a spare. As far as Michigan goes - I live very close to Grand Rapids and have to go there fairly often. It's a good town; I wouldn't worry about theft. BUT - Michigan has "no fault" clauses on insurance. I wouldn't dream of trailering it here without full coverage insurance. In Michigan, if some teenaged girl rear ends you while sending a text message and destroys your PWC and trailer - it's not "her fault," and she's not liable for your damage. YOUR insurance has to pay. If it's not fully covered, you lose it. Your vehicle insurance should cover your liability - meaning if it somehow gets disconnected and hits another car, it will pay for your liability, but will NOT cover your seadoo. You would need coverage separately on your boat. Some food for thought... Have a great trip! Riding on Lake Michigan is a blast.
2014 Spark HO iBR