We've done hundreds of flips and have always used Quickbooks Online Plus. 

You can create separate notes for different types of tasks or routines, and it’s all stored online, so you can access it from anywhere.

I've traditionally relied on an Excel sheet, but it's not always convenient when I'm away from my computer.I recently came across an online calculator that seems to provide detailed metrics, including Cap Rate, IRR, and others.

How did you evaluate the returns (ARV) of an agent pulling comps or through your online resources?

It seems safe to assume there's a market, but obviously we'll need some more research to confirm that. 

The move is always whatever SAFELY leads to owning more assets.

You can learn from books, talks, online lessons, meeting people, getting your money ready, looking into things, types of houses, help from someone who knows, and lessons from pros.

As for the shed I was recommended to allocate it the same way split between the properties therefor making it fall under the De Minimis Safe Harbor amount of $2500 allowing me to expense the cost rather then carry it as an asset for depreciation.

These specialized companies, easily found online or here, will create your company's SD 401(k) plan.

Capital partner is a very safe way to go.