Can you tow your 1999 Mercedes Hardtop Convertible behind your motor home by putting your car in N and then pressing the tow button - does it disengage the drivetrain?

Yes, you can tow it that way. No. It does not disengage the drive train. It is also likely to wreck your car if your steering wheel is not locked so that it points straight ahead. It could also tear up your transmission. It is also illegal in some places. An exception occurs in some of those places occurs when the car is broken down and you are taking it to a repair shop, otherwise you get a ticket. Still, you can try if you want to.

If you have ever noticed cars going to races or car shows are not towed that way. Race cars are not towed that way. They are usually towed on a separate trailer.