I’d approach it as whatever will satisfy the bank, will satisfy me also. (The bank is a lot more picky than I would be).
In our case, the bank was lending on the “park” not the “homes” but still had a problem with our office-mobile and storage shed (owned by the park) which were in the 100-year flood plain. They required flood insurance (and hazard insurance too). So, we got insurance. The bank told us how much coverage they would require (their appraiser for the property also appraised the office & shed) and we went to our agent (Kurt Kelley) and got the coverage. It was only two structures and didn’t cost much (about $670 for a year). I’m sure the cost of the insurance will vary depending on the replacement cost or depreciated value of what you’re trying to insure, though. If you’re trying to insure new homes, it will certainly cost more!
We own other homes at this park and the bank was going to require insurance on those homes as well, until we proved to the bank that those other homes were owned by a competely separate company. So that’s another reason to keep your “homes” in a separate company from your “park” company. (See recent “Business Structure” discussion in this forum).
Hope that’s helpful!