They don't mind higher vacancy rates then SFH might be an option.  

However, I am unfamiliar with any lenders having traditional mortgage options for anything with a VIN number such as a trailer.

How did the price compare to other options?

Speak with a lender now to understand your options and start building a plan.

If I have several options, I would prefer a HELOC with no initial draw requirements (i.e. to establish a literal line of credit that I have no specific short term plans to use), i.e. not something like the better.com HELOC. 

I’m not sure a bank would be your best option but it can’t hurt to try.

Fortunately at my rate they have some cash flow and good appreciation.The rates make it rare that the brrrr is the best option available.  

Lots of options as far as raising nightly rates as other STRs shut down, converting to MTR or LTR or doing an exchange to another state.

But that will be your decision and at least you have options.

If that's what you're really after I would start with the basics of what kind of bank loans either residential or commercial are available to you - not saying this is the best option, but it's a good place to start.