You can certainly do long rides on a 250... as long as the bike is physically comfortable for you and you're not looking for crazy mad power, a good 250 will take you anywhere you want to go. The specs you listed, though, that's a heavy bike for a 250, so it might not be easy to wind it up and get it up to highway speeds. I know a couple people who have toured on little Honda Rebel with no issues. You main problem might be parts availability if something does break down along the way.
Still, were I in your shoes and thinking about a trip like that, I'd get something with a bigger engine... Heck, I recently bought a Triumph Bonneville, 865cc engine, but it's a newby friendly bike. 500 pounds, but it's so well balanced a rider doesn't have to manhandle the weight around, the throttle is not at all touchy, brakes nicely but not overly touchy... There are a lot of options out there for you, just depends on your price point.
But if that Kymco sings to you and it's THE ONE...you could tour on it, and have a wicked fun time. So you don't tear up the highway...as long as you stay out of the fast lane, so what?
