Unless this is some type of homerun deal, which I assume it isn't if the mortgage is upside down, then why bother?

This policy will provide additional coverage above what your existing policy covers.

I don't see similar features in existing cabins and my gut tells me that it might be nice draw when weather transitions from summer to colder temps. 

One has no mortgage, their other has a HELOC for around $20k remaining and is coming to its 10year term that was established before placing with LLC.My predicament is how/best way to pull equity out of either property for a down payment for the 3 family that is valued around $450k.

I had a similar idea (having one of the mortgage brokers I know underwrite any prospective buyers.

You should ask to speak to the commercial lender at the bank that carries your property's current mortgage.

There's also a detached two-car garage and workshop.It exists in kind of a twilight zone between commercial and residential. 

Rent payments from the medical LLC are fully deductible as a business expense, while the property-owning LLC will report the rent as taxable income, which can be offset by deductions for expenses like mortgage interest, property taxes, maintenance, and depreciation.To ensure compliance, document how FMV was determined—using market comparisons, an appraisal, or similar data—and draft a formal lease agreement outlining the terms, rent amount, and responsibilities.

Getting a property with a 3% mortgage that offered both equity appreciation and solid cash flow is what sparked my passion for real estate investing.

Income would be from hunting dues and timber harvesting, expense would be conservation management, taxes, and the mortgage.