My LTR income has provided the cashflow to quit my job as an electrical engineer.  

Sure the concept is good (search engines), but you backed the wrong horse.

Starting in Highlands neighborhood (or northside) which used to be a very rough part of town, is now the one of the top 3 most desirable are in the metro and this has slowly trickled down into neighborhoods south.I am an engineer so I love to base my decisions on data, so for example looking at census data, I like to look at % of high income earners in an area to gauge if I should invest or notFor 80204 which includes the neighborhood of Villa Park, in 2010 the % considered upper middle/high income was 4.2% of households. 2022 census says that now it is 40.5%On the other end is 80219 which includes the neighborhood Westwood which would have the lowest income area on my list, in 2010 Westwood had 4% as well, by 2022 it had 21.1% high /upper middle income earners.I have properties in both and tenant applicants are a wide variety (lower income folks on rental assistance to high income earnings wanting to rent in an area before buying a home) so its hard to put a property class in this area. 

so much private land has been logged and replanted since then.. in those days we would buy a 40 lets say for 150k  take 200k of timber off of it then sell the land on contract for same price then hypothicate the note to pull out more cash rinse repeat.. we also would use our logging roads and staging areas stratigically so when we left the roads were in the right place to do a 4 way lot split and the landings/stagging areas became the building pads.. in the NW permits for logging are not tough.. in those days it was over the counter and there was nothing you needed to do with regard to excavation.. however if I just bought the land and wanted to put in roads and pads then I would have had to get a grading permit and all the survey and engineering that went with it.. its was really something how we did that.. and I miss it to this day.. the other item that made it so profitable was Japan was paying premium for Export quality doug fir logs.. you could get double or more for export logs.

The downstairs tenants are a young couple, one works about 30 minutes away and the other goes to school as an engineer.

I am looking to start Real Estate(primarily focused on House Hacking and SFH if it goes well) as an engineer after graduating.

I’m an engineer by degree and have worked on a few septics during my excavation years.

For example, parking under the building would require steel, if the spans call for it you could need steel.Also, just because you are five stories or more doesn’t necessarily mean you need steel either, or perhaps you could do a mix of steel and wood frameLots of variables and really need a plan set and a structural engineer to sort these things out

You could try hiring a structural engineer to do structural drawings for the house

The demographics of these investors are typically high income earners, almost 90% working in tech (software engineering, tech sales, computer science, etc).