About to begin a historic renovation project in which the owners want an elevator or lift installed.

Outside of biking distance is much less expensive but desirability and rents drop way off. 0.25 miles (walking distance) - 2 miles (biking distance) tends to be the sweet spot, at least IMO and for my market.Good point made about flood insurance too, and that is NOT optional if you have a mortgage and rates are NOT negotiable, but set for the market ... become familiar with the map of flood zones ... if you can get just outside of the flood zone (depending on elevation as well as ocean proximity) and still in the sweet spot, then that'd be double sweet.As for hiring a realtor to fill it, manage it, and charge you a % ... depends on the realtor, depends on the %, and depends on your goals, availability, and willingness to self manage, but in a vast majority of cases, especially with a vacation type rental, it will most likely be in your best interest to self manage, at least in the beginning if you only have 1 property and little experience. 

I wonder if this is because the flood map boundaries are not based on elevations?

In Norco, La alone there are 3 oil refineries, 2 chemical plants(one of them makes the household weed killer, Round-up) and a grain elevator... so you are looking at hundreds of workers all needing places to stay.

Also out of state property owners.Because I am not going to be able to qualify for a conventional 25-30% down payment loan (and I don't have that much cash), I was hoping to work something out in the neighborhood of 5% down and a slightly elevated interest rate over the life of the loan.

They are prone to disease, and insects especially in the lower elevations.  3.  

Their rate is much cheaper than the FEMA one and didn't need elevation certificate.

If unsure or unable to determine from map, I call my agent who looks up the elevation on the SPECIFIC property.I do a lot of the above before even seeing the property as I have all the sites bookmarked and can do so quickly.

That's pretty common in flood zones to help elevate issues a bit.Not sure on how to estimate for flooding emergencies.

@Joe ConklinIs the house elevated(off grade) or a slab?