Ned,
I'd vote for the carport too, but not for the screening. I have the impression the new place is somewhere in east Virginia? Not too much snow, most years, but lots of thunderstorms. And when it's rainy and windy like like, the rain comes through screening, even if there's a good overhang, like it wasn't even there. Worse, you *will* get sawdust on that screening, and it will look like heck, no matter what you do, you won't get it all off, and then it'll rain, and all that sawdust will get wet, and musty, and moldy. Don't ask me how I know about screen porch woodworking in east virginia...
Seriously, clear stretched 6 mil plastic, well framed and anchored, covering three sides, would be far better. You could enclose that space for less than a hundred bucks, and get at least 3 1/2 seasons of woodworking in every year. By the time you needed to replace the plastic two or three years on, you'd have a much better idea of what you want to do...
Thanks,
Bill