I searched around in SD for a Ninja 250 for about a month before finding one that I liked and met my criteria. The person I purchased my bike from lived about an hour away on both country roads and a busy superslab. I choose to pickup the bike with a u-haul trailer for ~$15 for the day. It worked great. No problems with loading and unloading the bike using the tailgate as a ramp. Just make sure that you bring 4 tiedown straps.
On the Ninja 250 vs. 500, the girl that I got the 250 from was selling it because she had upgraded to a Ninja 600 after just 6 months. She said that is was very similar to the 250 just a little more power at the top end (highway speeds) and weight for the freeway driving that she does. My experience has been that the 250 is an excellent bike to learn and improve your skills on. I had previous riding experience on dirt as a kid and some street bike riding in college. However, I am really glad that I choose this bike to return to riding on and I’m enjoying the Ninja 250 on both commuting and weekend rides. Mind you my rides don’t include much freeway driving, but the Ninja 250 Riders Club has a ton of information on that bike (Ninja 250 RC FAQ). Many of them ride everyday on freeways.
Good luck in your search.