Even with a high-level of trust, I would get a full appraisal and inspections.I think the simplest structure might look like this.  

2) Maintenance: almost impossible for a PMC to stay in business and not charge for their time to handle anything but the simplest maintenance issues.

I suppose the simplest way would be to create a new LLC with you and your wife as shareholders and put the STR in that entity.

It cannot be done, save for the simplest of tax scenarios.

Then each own 50% seems like simplest terms.

A lot of people may consider these options borderline reckless, but I've used the following sources at different points in time:Credit Cards - You can cash advance or pay suppliers directly.Personal Loans - I've used the following: Prosper, Lending Club, SoFi, Best Egg, Discover Personal Loans, USAA Personal Loans (these are by far the simplest, if you're a member).

The simplest answer on how to structure this deal is - Structure it in a way where both of you are comfortable with the terms.If I were in your shoes I'd follow what @Jake Handler suggested.

If you don't have an on-site tenant, then hiring a property manager might be the simplest way to go. 

Simplest and easiest, high yield savings account or Money Market Fund.  

Again, you're side stepping the biggest SIMPLEST fact, all these potentials for how to do a transaction EXIST, and have for YEARS....