I lived through the outskirts of
Camille in 1969 as a child, and a direct hit by
Frederick in 1979 as a young adult. Not being in a flood plain, your biggest worries about Matthew would be wind damage to your house, and damage from trees to the EAST of your house. Primary winds at their peak will be coming almost due-westerly. Potential damage will be from: 1) wind, 2) water. If you have a decent roof, rain shouldn't be a big factor. But winds could damage the roof deck, or bring a tree down on your roof - fallen trees, and tree limbs are the cause of most damage in residential areas.
OP - give yourself a break. Florida hasn't received a 'direct hit' by a hurricane in over a decade, and Matthew will NOT be a direct hit. It should skirt the eastern Atlantic seaboard, then move out to sea. Depending on how far WEST of the east coast you are, you should be fine. It's the aftermath and potential cleanup you'll have to deal with.
It's wishful thinking to hope that neighbors will cover your windows with plywood while you're away. The expense and time needed are prohibitive. After the storm, consider fitting your largest windows with plywood 'storm windows', and store them in the garage. If you were home, you could put masking tape on the larger windows to prevent shattering in case of projectiles, but that's most important if you're going to receive a direct hit. Hurricanes spawned 'mini-tornadoes' can cause lots of damage - the extremes in low pressure they generate can cause well sealed buildings to 'pop' - we always kept windows cracked open an inch or two on the leeward side of the storm (west facing windows in your case).
In Frederick, we lost 10 trees, but none of them fell directly on our home. We were a little surprised to learn we HAD 10 trees - it didn't seem we had that many until we had to chainsaw them up and cart them away. I bought a chainsaw from Sears, and sawed up neighbor's trees into 3-ft sections for $10/tree. Cleaning up my first neighbor's yard paid for the chainsaw. We lost power for 7 days, and city supplied water for 10 days. We did okay with no power (generator for the freezer), but going 10 days without water was terrible. Debris in the streets made normal driving impossible until 2 or 3 days after the storm. Hard green pine cones, and roofing nails were EVERYWHERE - expect to find at least one in your tires. We found the aftermath - which lasted for days/weeks to be much more stressful than the storm itself which roared through and was gone after a few tense hours.
EDIT: it was fascinating to me after the storm to see 99% of the trees in the region had fallen with their tops pointing due west. Now I know it depends on the location of the eye of the storm relative to your location. In the case of Frederick, the highest winds were in the Northern sector of the storm that passed directly overhead. Matthew's winds may be primarily from the NORTH or NORTHEAST depending on how far off the coast the eye passes.All you can do is enjoy your vacation, and try not to worry. You're in the best place you could be - evacuated, and safe. The aftermath / cleanup is never fun. Here's hoping you have little damage, and lots of memories. And although Matthew organized quickly, and with little warning... be ready for the next storm. You may even find neighbors have left plywood sheeting in your yard... plywood that's blown off THEIR houses. But seriously... at this point there's not much you or anyone can do against the force of nature except live through it, and have better preparation for next time.