For an easy-to-use, durable, one-part paint Interlux Brightside is very good. We use it on the wood window frames, doors, etc of our boat and if the prep and prime is done correctly it holds up very well over time in the weather. I know several people who have painted their entire boats (some wood and some fiberglass) with Brightside. For larger surfaces it can be thinned and sprayed but most of the people who have used it on larger surfaces, including us, use the roller-tip method.
I'm not saying Brightside is the best exterior paint out there. It's not. But for the kind of project you're describing it might be the most cost and labor effective solution for you.