Where I mention the 3-5% delta on a second is that is what it will cost you from a traditional bank (for example a HELOC or 2nd mortgage).

Think of it this way - the 6.00% cap rate is your cost of equity.

I ask cause an architect costs money and Im not rich.

This raises the cost of using an STR versus using a hotel. 

@Patrick Mulligan @Antonio Hernandez has good points about closing cost and such.

Population Growth: 49% Population Growth over the past 20 years, Sacramento has experienced a tremendous growth in population with individuals and investors alike coming in from the Bay Area seeking more affordable costs of living and lower barriers of entry into real estate. 

Real Estate is definitely not just a "numbers analysis" and you are definitely thinking about things the right way - but I think a good next step for you would be to spend some time putting a lot of this stuff into a (very) basic financial model/spreadsheets mapping out all the potential costs and estimates on effect (effect on value, on exit, different scenarios) - I think getting started with that framework should help with these decisions immensely

This includes having a clear understanding of holding costs, financing options, and potential rental income once the property is ready.Your current realtor’s local expertise will be invaluable as you navigate these challenges.

EDUCATE YOURSELF - yes, it will take time, but will lead to a selection that better meets your expectations & avoids potentially costly surprises!

If you have $50k to invest then you will probably be looking at properties in the mid-to-high $100s (assuming you're putting 20% down + closing costs and a little cushion).