Yeah i'd agree with either of those. an across or a zzr250 would be good. the across would be a bit better for the boot value as well.
oh and r.e. cb250, i did my L's test on one, thought it was a very average bike then with next to zero experience (i could feel the vibrations even at those pottering-about speeds we did). I went back and did my P's test on one 6 months later, and fark me i was running int all kinds of "you-want-to-rev-me?-i-dont-think-so!!!!" issues after stepping off my el250 (cruiser bike based on the zzr250 engine, so it revved quite happily:twisted: )
the zzr250 was a pretty easy to ride bike from day one, heard similar things about the across too

. But that's just me, some people may think the cb250 are great bikes, i just think she'll encounter problems just keeping up with traffic after she's gotten used to riding.
b.t.w. good on you for the conversion!!!!!