It would work well in a carport, you just have to sit a layer of plastic under the top before you paint, the debree in the ceiling of the carport is a hazard, but if you do use a carport, you will need lots of ventalation and it has to be a hot/very warm day since your painting in the shade, I usually start taping at 10am and start to spray around 12:30 1 pm during the hottest part of the day. for vetalation you can use regular house fans I've seen them used often but keep them far enough away not to catch fresh spray, some have used old blower motors from heaters and just reversed it, whattever they can dig up. As for walls, you can put filters up, its actually better but not alot of people like the work. Go to a home depot or lows and get some filters, they are usually sold in a box containing 100 18" square filters just duct tape them together to make up your walls, they are made of course woven fibers they are usually a light seafoam color. As for the floor, unless you have a downdraft paint booth yes, soak your floor, it keeps whats down there down there and it attracts loose dust and dirt and keeps it there, if your floor isn't smooth, squeegie it off first so you don't have any splash up on your paint, if you do no worries most of it will evaporate and the rest you can color sand smooth. Always paint with a mask on, I use a 3M double filter version, you can get one for $45, never paint or letr fresh paint out below 70 degrees F, the clear will turn cloudy, the warmer the better, the dryer the better. So pick your painting days well and you'll have a good clean job.