I also think I would pick a dual sport, much as I like vintage bikes.
They are tough, soak up bumps, tend to be light, easy to work on.
Nothing seems great, the dr650 is a bit too big and heavy, the 250's too small and under powered.
A dr400 would be nice.
Once out of the US and its high speed limits and wide open interstates, the 250's would do real well.
I think 95% of bikes in other countries are 250cc or less.