If I were you, I'd just run the numbers, they'll tell you what's worth doing. I have no short term rentals, but this applies to any business. You need to know how much you can make, and how much it'll cost to make that money.
I would:
-Figure out what the average occupancy rate is and then pad it by 10-15%
-Look and see how much similar units are renting for, and pad it by 10-15%
-Get some quotes for house cleaning, since its going to get really old cleaning that place over and over again after guests leave it a mess
-Get some quotes to figure out how much it'll cost to build the houses, build the driveway, lay the septic, run the power, dig the well, etc.
None of that should cost you any money, just your time. If you do that and it looks like you'll still make money, then run with it.
Also, if it were me, I'd probably figure in a finance cost. Basically, I'd figure out what the monthly payments would be on a loan to finance the capex and subtract it from my revenue. That's essentially the "cost of your money", even if you use cash reserves to do the original building.
One last thing--I would probably build the houses as "real" houses, so you could long-term rent if you get tired of short term rentals.