deck and floor paint on 18sf. help!

[dginge]

I'm thinking about painting the deck and floors on my 18sf
Floor solid and original. Original gelcoat. I really want to just paint over
My existing non-skid with a roller and not do the walls ? Bad idea?
I could brush the small strip of non skid on my deck up top and
Do the floors pretty easy? I also would like to do it myself but wouldn't mind paying someone
What paint and is this an easy task? How much is most good paint?