I have not come across a rate that high.

All advice is much appreciated. helping me make my decision. mostly thinking about 5-6 until apts building somewhere for 12% cap rate or possibly higher. 

The property is currently being used as a primary residence (looking to move to CA) and was purchased in 2021 for $650k with a 30-year fixed rate mortgage and PITI is just over $4k per month today.

The location is growing and its the safest city in that entire county. home-ownership rate is very high like 85% most of the homes were built in the last 24-36 months.

Current rent rates for all 4 tenants are well below market rate because of the condition of the property.

That email should start with a breakdown of the estimated purchase price, rehab costs, estimated income, and return on investment assuming prevailing interest rates. 

With less competition, if you have good theming and design then it'll be easier to charge a higher nightly rate and keep your property full which will make it more profitable.

In calculating the Net Present Value of the investment, what is the appropriate methodology to use in arriving at a discount rate?

To make wise investment selections, be aware of area trends, rental rates, vacancy rates, and property valuations.Keep in mind that investing in real estate is a journey, and there will be obstacles to overcome.

The rate will be high but you won't have to provide any income documentation or leases.