Weekly farmer's market, multiple LARGE cultural festivals, a sufficient music scene draw, some minor league sports arenas (Hockey, Basketball), and a flourishing LGBTQ+ community to boot.   

No sweat.As a real estate investor you need to maintain sufficient reserves for the unexpected.

My plan is to acquire a portfolio of buy and hold properties sufficient to support my husband and me in our retirement (~20 yrs from now), as well as to create a legacy for our children.

I assume that I can take possession (change locks etc) and perform structural repairs sufficient to bring it back to habitable standards but my question is does that include sprucing up the property itself ie tree trimming grass cutting and the like to maintain neighborhood norms?

If that case, your W-2 withholding might be sufficient. if your AGI is less than 150k, you have to make lesser of 100% of the tax shown on your PY return  or90% of your tax for the current year. 

Each month's rent payment may consist of not only the rent, but an additional amount which can be applied toward the down payment on an already specified price.legal descriptionA property description, recognized by law, that is sufficient to locate and identify the property without oral testimony.lenderA term which can refer to the institution making the loan or to the individual representing the firm.

And if a buyer gets "cold feet" as was said, they need to use that as motivation and then find a valid reason to get out of the agreement, but "cold feet" as far as I understand the law as a layman, is not going to be sufficient. 

Im just thinking about, in the event I want to move out / purchase the next property, how much I may be paying out each month to hold on for potential/eventual payoff when I sell.And how long would it take for sufficient appreciation for a decent return? 

Rul. 8429039, provided that a two-year holding period is sufficient to ensure treatment as a tax-free exchange (all other tests being met). 

This sounds like the price is too high or they have found a better deals after closer look.It really depends on many factors, like what is the exact location, what is the shape of the lot, how is subdivided,  how is it accessed, how far are the closes utilities, are those private / public, is there any public access, are the access sufficient or do you have to build a new roads etc.