Why struggle with powerline adapters? Get a pair of Ubiquiti Nano Station Locos and be done with it. Reliable, encrypted, and not all that expensive.
I wouldn't call it a "struggle" so much, they both have their place, IMO. I'm a big fan of Ubiquiti Layer 2 Transparent Bridges and have installed about 10 of them. I've also have used PLA's in a couple of places and they work great, at least in my application. Sometimes they don't work because of being on different legs of the 120/240 or other issues that make them unreliable.
A
pair of PLA's comes to about $50, 2 Loco's about twice that much. The PLA's are in and working in about 10 minutes, the Loco's a couple of hours, at best.
But in this instance, I tend to agree that the Loco's might be a better choice, even though they cost more and aren't exactly plug 'n play, because of the OP's location...Florida, otherwise known as "The Lightning Capital of the World". Where I'm at in neighboring Alabama we have some horrendous lightning storms as well and I think the Locos would fare better than the PLAs after a nearby strike that could induce some surge on the power lines.
I NEVER string Ethernet cables between homes and barns/shops/guest houses out here....UBNT all the way, baby. A pair can be purchased that's already configured or you can configure with
this guide from UBNT.
Below is a drawing of the schema from house to garage and below that a image of my homemade, rust-proof radio brackets. Shorten the vertical PVC pipe for Locos, its shown for the taller Nanostations.