This would include doing mainly flips so i can get a solid return from that money or possibly even doing private money lending. 

My main goal is it be able to retire at age 40 from my main job and work entirely on my real estate portfolio.

Main thing to watch out is DSCR Ratio.

I'd like to add another SFH to the business  in the near future with the main goal being grow the business as fast as possible. 

Now my main issue is I need a fire detection system in a enclosed back porch that leads up to all three floors, but I don't know what's the minimum I would need to be compliant or that the fire marshall is suggesting what he wants or recommends.

What’s your main focus, or what are you hoping to get out of your journey here?

What are your main investment goals—cash flow, appreciation, or something else?

Hopefully this helps clear up the main point of your post!

I currently own and self-manage two STRs in Maine and should be closing on a small 'cabin campground' with 10 cabins nearby that will also be operated as STRs. 

A couple thoughts on your question:I tell our STR investors in Colorado that their main goal should be to set up the right way right out of the gate.