Just returned from a trip and saw this thread, so am giving a quick response, but will be happy to supply more detail later.

We went to Vilnius in late 2019 and had an excellent guide--Regina Kopilevich.  Her email is regina.kopilevich@... . 

I recommend her highly.  Her English was excellent, she was very knowledgeable, and she took us all around Vilnius.  She even tried to help research our family.  

Like Susan Gray, I highly recommend visiting Kaunas.  Regina did not accompany us there, but she told us exactly what to do.

Regina did accompany us to Daugavpils, which was another ancestral home for us.  She seemed to have connections there as well, and was able to show us around and introduce us to someone there.  She does not have a car.  She said she could arrange transportation, but we made that excursion on very short notice, and she wasn't able to get us a car and driver.  We had made a note of the driver who took us from the airport and we were able to reach him and have him drive us there.  So we were lucky.   I suspect that, if we had advised her of our interest earlier, she would have been able to arrange for a car and driver. 

Gail Marcus
Bethesda, MD