Suzy, the SCCA discussions really have covered all the options. "Reasonable" no longer exists, forget about that. "Affordable" usually means "major medical only" and you'll have to deal out of pocket with anything except being hit by a truck. And even then, the annual and lifetime policy coverage limits are incredibly low.
US insurers may not cover you overseas, and overseas policies may require that you not be in the US. Again, lots discussed in the SSCA forums. You may have to cast an eye towards where you will be going, and whether you think the medical care there is good enough, or whether you also want medevac insurance back to the states. That's another catch: Many policies cover only the injured party, and many airlines requires someone to accompnay you. If you look for medevac, look for a policy that allows a partner to accompany you.