This little hint/trick may be insignificant but was important to me.
(Always remember that my Winnebago is 12 years old, but good)
Re: Furnace floor vents.
There are 3 in my rig, bedroom, galley and near drivers seat. The bedroom one spurred me into action. In the middle of the night for a trip to the
loo, I would have to step on that vent with raised ridges ---- ouch.
I found a 'flat-topped' vent (strong plastic, in a local RV shop). The length was close but I had to cut a bit of the bottom insert part off to make it fit in the hole. Voila, my dream came true.
2. The other vents did not bother me for that reason, but they were rather dingy and had rust around the edges. Off they came, a little sandpaper to remove the rust, a cleaning with a degreaser, a good rinse and dry, then a spray paint application with my favorite color - slate gray -

using 'RUST-OLEUM
R. Should be good now, like new, for another 12 years.
A little side hint: If you feed your dog/cat kibbles near the vent, put a mat over it. This was also a good time to vacuum out the air duct and clean it.
carson FL