In a couple weeks I'll be driving through Armenia (crossing from and to Georgia) for a couple days.

I'm not worried about the driving per se, as besides Canada where I live I have extensive experience driving in crazy places in South America. But I'm curious about anything that I should be careful about or could be different from what I'm used. For instance:

1) Should I expect tolls?

2) Are police checks frequent? If so, what should I expect?

3) Is it possible to use a credit card at gas stations?

4) Anything else that you might think could surprise a foreigner.