@sam Thanks for the nice response!
I might do another post with a more detailed itinerary of that trip, which trains or buses at which times. But for what I did in especially Tbilisi and Batumi you can also easily find on wikivoyage so there's not much for me to contribute imo.

And even writing this post took quite some hours and as you can see on my blog, I'm not a regular blog writer, more just write something in case it comes up. :)