Can you develop some sort of a saw-horse and canopy type arrangement?  Boat supports just a foot or so off of the groud is high enough, but a little higher a little better.  Maybe the canopy is simply an a-frame tarp set up, or a lean-to attached to a gargage or house wall.  If the sun and water is kept off the boat, if the surrounding air isn't much warmer than ambient, and the critters (large and small) are kept at bay, the boat can keep nearly forever that way.  And whatever is set up, make sure it will remain set up during a good windstorm.

Again, I think the key is no UV and good airflow.  On the occassions where you get any slight wetting due to condensation or dew or rain splash, that doesn't seem to be a big issue if everything completely dries every day - I know that's a big IF in Florida.

As a kid in Michigan I knew where there was an old birch bark canoe - probably 60 years old - stored on two supports sticking out from the side of a log cabin wall.  The canoe had it's own sloped little roof awning built over it. Perhaps the canoe is still doing fine - it was for the 20 years or so I observed it under these conditions of occassional use and excellent storage. I don't know where the canoe went - the cabin became part of a resort beach access and the rest is history.

I'd avoid any sock-type cover or anything that doesn't allow good airflow.  And I learned the hard way that a dark colored tarp touching the boat in full sun is enough to damage the epoxy on these boats.

   The place where the canoe was located, on the lake where I grew up.  (But to be clear, this picture is from a little before the time I was born - sometimes the "interweb" is a good thing for historical research.)  Memories fade, but just maybe the canoe was located on the right side of the center-right building, above what looks like a washtub or bow of a different boat or something.  I expanded the picture and just can't tell, and can't remember. Perhaps I see the slightest hint of an awning there. 

And pretty soon John is going to have the runabout kit ready so that (in my mind) I can pull up to the dock here and feel at home.  Maybe I just found a name for my runabout when I finish it.  And are those some time-traveling NE Dories with the sterns squared off that I see here?  Gives one some food for thought!!

p.s. - The place has always been a resort, in my previous post I meant that the property was bought out by a local ski resort and "grossly" modernized.  But that's life and progress.  You don't want to hear about the time I saw a drunked-up waterskier from downstate hit the modern aluminum dock that replaced this dock!  I'm postitive he had to spend the rest of his vacation in a cast.

   I've been on the web "down the rabbit hole" as they say for the last while now.  I had no idea this book, puiblished in 2011, existed. https://books.google.com/books?id=8ZoKUFQ5QDUC&pg=PA74&lpg=PA74&dq=fisherman%27s+paradise+bellaire+birch+bark+canoe&source=bl&ots=jPCe3Rw_da&sig=ACfU3U31IiRmaogg9rHUEDLWeedbMChtvA&hl=en&sa=X&ved=2ahUKEwi8wfa8lq_rAhVMXq0KHVpmC0oQ6AEwGHoECAgQAQ#v=onepage&q=fisherman's%20paradise%20bellaire%20birch%20bark%20canoe&f=false

But the point being, the author ended up being our next door neighbor on the lake, and just about everyone mentioned in the book are the parents of all the people I grew up and went to school with.  Bill's girls were Shannon and Shawn.  Anyway, see page 74.  It turns out that perhaps - for at least much of the time mentioned in this book - the birch bark canoe was under the eaves of the front porch there at Fisherman's Paradise.  I'm not sure - but maybe that's what I remember - or maybe it's stograge location moved about periodically, or later in it's life.  If Bill saw the canoe in the early 50's and I saw it in the late 60's, the storage for it must have been pretty good.

What a cool walk down memory lane you had today! And such an awesome place to grow up. Thanks for sharing. And thanks for the suggestions. Right now I've got my kayak on a saw horse with a cover over the top. I don't feel like it's very well protected. I'll rig some kind of canopy for it that will allow for air flow. I'm glad I asked because I almost bought a bag type cover. I will definitely stay away from that. Thank you!