Your post above literally describes so much of our experience this past year when our immediately neighboring lakeside cottage was sold and turned into a VRBO rental. I love our cottage. Planned to retire there. After just ONE year, all of that is in question. Not even sure if I want to be there as a cottage. EVERY week is a “new adventure”, new people, new concerns. It has really impacted the “tranquility“ of our location on a dead end street lakeside. And even though the owners have restrictions, and have worked with us neighbors to strengthen them in light of problems and concerns, they are not their to supervise. Only us neighbors are.
I completely understand your situation. My wife and I own a cottage in northern Michigan where the lakefront lots are only 75 feet wide. After many years of great neighbors, the elderly couple next door had to sell due to health issues. The new owner, from downstate Michigan, seemed nice enough but we soon learned they would need to periodically rent the cottage to help with the payments.
Our worst fears were soon realized. One couple would rent it and then 5 more couples would also show up. Tethered lakeside boats routinely got loose narrowly missing our dock, hoists, boats, etc. The provided trash cans would get full, so trash was being burned in the lakeside fire pit (including baby diapers). More cars than available parking so trespassing galore. Noise and parties. Individuals, including their pets, routinely ignoring reasonable property boundaries, etc., etc., etc.
We started by constructively and diplomatically talking with the new owners about these unacceptable renters' behaviors. However, just like you, they were not locally around to enforce their own renters' limitations. We neighbors became the bad people and quite frankly we got really tired of no longer being able to enjoy our precious cottage when many of the renters next door innocently or intently behaved poorly.
Unfortunately we had to fight back. In talking with the township Department of Health, we discovered a septic and holding tank ordinance that limited rental houses to having no more than 2 adults per bedroom. Children 12 or older were considered adults. So the 3 bedroom cottage next door could be rented to no more than 6 people that were 12 years old and older. When more than 6 adults showed up we called the Township Department of Health and the owners were ticketed. We politely asked renters to not park on our property. When they refused to move their car, we called the sheriff and either made a police report on the spot or went into the sheriff's department and provided photos, etc., making a "trespassing" complaint. Copies were sent to the cottage owner with the suggestion that we were within our rights to have such vehicles towed away in the future. Finally, we discovered township minors in possession and noise ordinances that when violated did result in the sheriff making a lakeside visit. The result was tickets to renters and the owners.
After 1.75 summers the new owners gave up and sold. Our new neighbors are wonderful. They never rent the place out, have young children that we love to see running around and our area of the lake is back to normal. However, the almost 2 summers of enduring renters were horrible.
My advice would be to go to your County, Township or City governmental offices. In our area of northern Michigan there are many such issues with renters on our county's lakes. I found out that we were far from being the first to complain and that there were far more important/influential people who had already complained. The officials I talked to in the building code, health and sheriff's departments had all the answers I needed to every possible question. They were extremely helpful up to and including providing copies of applicable ordinances. (In fairness to the new owners next door, we politely provided all such information to them. After the first summer was over, the next spring we had to inform the owners that we would be calling the authorities if violations continued to occur. We then did as we had promised).
Good luck and hang in there. You likely have time (and local ordinances) on your side.
