I'd recommend a HELOC for your situation, especially since there is already good equity in the project.

However, and I don't know anything about AirBnB in Denver, but my biggest concern for this project is the ability to consistently rent the basement for $1,800. 

Being able to be on site and able to commute 20-30 hours a week on the project is crucial for me 

For that same capital, I can buy a run down project and renovate.

Both my wife and my background is in manufacturing, specifically operations, customer service, and project/account management. 

Currently I work as a Project Supervisor, we do rehab in multi-family units.

We are only selling completed homes with our own in house financing currently at 3.75%, a huge discount from most bank rates.We are a long time property provider for some of the bigger podcasters: Real Estate Guys Radio, Marco Santorelli (Norada), Kathy Fetke (RWN) Jason Hartman ( Empowerd Investor) GRE (Keith Weinhold), Whitecoat Investor Group and more We also work with American Homes for Rent, Invitation Homes, Crescent, Haven Realty (JP Morgan) to name a few on the institutional side We are partially owned as of 2022 by Sumitomom Forestry, which means we have no bank debt and self fund all our building projects.

Ask them if they have any projects they are seeking hard money on.

Really tired of paying taxes while the govt gives away money (let's not get political here please).  

However, as we delved deeper into the project, we realized that a complete remodel would be more beneficial.