Their combined income is below $100K per year.

Combine this with interest rates that are near the high for this century and cash flow is challenging.  

I am sure I will be very publicly wrong, and you all can make fun of me in two years, when stocks double and real estate prices crash 20% from here, but I just don't know how you can watch this industry, this closely, for this long, and not be raring to go in the current environment. 

I have three listings, 1. unit with a pool and hot tub, 2. unit with a hot tub, 3. both units together as a 12 sleeper.Gross monthly income (after booking channel fees) for the first unit over a 7 month period was $7309.Gross monthly income for both units over a 14 month period is $11,297 (after booking channel fees) As a long term rental the combined rent would be in the region of $5500.Is it possible to sell the property based on the income generated by the STR business or would the value always be based on bricks and mortar comps? 

A friend of mine invested in one last year—apartments upstairs, a small coffee shop downstairs - and the combination of income streams made it a steady performer.Scaling with a 1031 Exchange:While not applicable unless you sell a property, planning for a 1031 exchange could help you scale quickly while avoiding capital gains taxes.

Many benefits to doing so. 2) If you are going to invest outside your area, the one thing I rarely see mentioned here is simply the "investment landscape".

Rare incident?

If you're able to save $50-100K per year for 14 years (when you're 40), a combination of getting solid deals, paying down debt, and having a target goal of income vs expenses, it's definitely doable.  

The minimum sheen I would use for any rental is satin (Very rarely eggshell).Does your rate include cleaning fees?

They rarely have an over-leveraged emergency or catastrophe.Of course they will not grow as fast as the investor using leverage and NOT over-leveraging.