I'm from Singapore and planning trip to Eastern Europe, landing at Romania and taking a train to Bulgaria and back to Singapore.
If I buy a one-way Singapore-Romania ticket and another one-way Bulgaria-Singapore ticket, is that sufficient proof of onward travel out of the non-Schengen area or do I need a ticket out of Romania?
I understand it's okay for between Schengen to another Schengen area, but these is between non-Schengen and non-Schengen.
On top of that, how about Schengen to non-Schengen and vice versa?