I've noticed some really extreme discrepancies between renting and potential mortgage payments which make me hesitant to buy a primary residence.My wife wants to move around 56 (not too far from the ocean), which I don't mind because it seems they have great school districts and we have young kids. 

Shortly after, I noticed another listing using my property photos but with different rent prices.

The return on equity is probably very low considering they are paid off so maybe explore refinancing or selling the lowest performing one(s) or your biggest headaches to reinvest in more lucrative deals.I noticed you also used a metric of number of rentals to attain your goal rather than $$$/month.

Most of my clients:1) Put 20% down for a conventional investment loan.2) Put 10% down for a second home loan3) Something else, either hard money, DSCR, or portfolio loans.These are the most common ways. 

As far as appreciation, and someone can correct me if Im wrong but looking at all the common markets over an 8 year span, its about the same for all of them.

(Luxury mansion or hosting your home while on a vacation)Have you noticed that your bookings are coming in a chunk?

Common fees will include a set-up fee, a leasing fee for each turnover or a lease renewal fee, marking up maintenance, retaining late fees, and more.

And has anyone noticed any particular nuggets to look for?

To gain investor confidence, ensure the investment property numbers are real, use the most common contract forms in your state (versus a 2 or 3-page) internet/guru contract form) with appropriate addenda, or an attorney-drafted form and attorney-drafted assignment agreement.

One option I haven't noticed being mentioned is to auction it.