About 23 years ago I began my quest for my ancestor's ethnicity. Nobody knew. Once I figured it out, located the village, figured out I am half Rusyn and visited with cousins, I decided to share the strategy I used with the world. For free. So I created a site to do just that. A brain dump of everything I know about research in Slovakia (and nearby). That site is called www.iabsi.com. It's not intended to be Rusyn-specific, but given the preponderance of Rusnaks nearby, it's a big help. I've had lots of contributions over the years.
The strategy has been a dead-ringer for so many people. All it takes is some gumshoe on your part to get there. That's why I keep it up and keep paying the hosting fees every year.
Well, I decided to go back and do a big refresh of the site. The strategy remains constant, but there are some new resources that make it even easier. Of course, I will be fixing the broken links that inevitably occur over time. The changes will come weekly, over the coming months.
If nothing else, read the strategy page. I hope you find something if use in there.