Given the single tenant, I haven't had to solve this problem, it is however on my mind.

They understand that there's value in what they provide, which is steady, documented income, minimal turnover, steady payment, quality references, no drama, and peace of mind.

Keep in mind even their prices can vary widely, and until you have more experience, it will be hard to differentiate between reasonable and not. 

Keep in mind turnkey companies do get bulk discount from their subcontractors and vendors, some company pocket the discount for themselves, some company pass onto the discount to their customers and offer a great price.

It'll give you peace of mind. 

You also need about 20-30% down on land loans so keep that in mind!

I’m weighing this as a potential long-term hold, but want to be mindful of any unique risks that come with this structure.

The other half of the accounting records is coming from online purchases, utility payments, etc etc where they are sending you an email. 

Now they write the offer and send it online.

If that's the case and you aren't viewing more properties in person than you are making spreadsheets on, you are destined for analysis paralysis.Spreadsheets can only tell you estimations based on numbers given to you online or by a real estate agent whose job is to sell the property.