I am assuming that you are talking about just painting
the rubber/insulation/Ensolite, and NOT any of the fiberglass. Fiberglass would require much more preparation and care than the Ensolite to get a decent finish, and I would highly recommend boat paint designed for fiberglass if you are planning on doing tat, although I know that others have used different paint.
the Ensolite is quite easy, and I have put up a video on caulking the joints and painting at
The MOST IMPORTANT PART OF PAINTING THE ENSOLITE IS PREPARATION! Make sure that you clean the Ensolite as well as you can. Use Spray 9, rubbing alcohol, degreasing cleaners etc. so the paint has a good, clean surface to stick to.
Make sure that you use a good quality primer, like Zinsser Bullseye 1-2-3, then paint over that with a good quality acrylic (water based) house paint. We like Benjamin Moore products. We used 2 coats in our Trillium
. Looks great.
Go at it, and good luck!