Furthest I have been - a couple miles off-shore. In theory, could glide to landing on a road or beach. In reality, really did not want to have to explore that option. It is called the Chicago skyline tour, and I fly really well maintained planes but still recognize that it is a balance of risk vs reward. Sunset over the Chicago skyline with ORD and MDW landing traffic is breathtaking. Lake Michigan is unforgiving year round, not to mention the boats, beachgoers and road traffic really make it risky if I am suddenly engine INOP.
The warmer the water, the more survival gear you have onboard, and related only reduces the maximum impact of an engine failure. But, this is an example of a topic that has come up many times, which you can see in the similar threads section. There haven't been any advancements in single engine over water technology that would negate the information in those other threads.