Should I visit Ukraine or Russia?

[el_guero]

If that is your plan, I might suggest Kiev and Moscow.  There are flights and trains between the two.

If $200 more for visas is a lot, you might just consider Ukraine.

Yes, you can teach there.  Although you are supposed to get a  business visa.

Cultural differences?

Not much for me - "they" are very much like educated but still "traditional" Mexican men and women.  They are interested in serious men.  Players abound there just like they do here, and women just don't seem to want to waste their time on a foreign player over a local player.

I gotta ask, what in the world do you expect to find in S. Korea?