Solo Driving journey through Eastern "Europe"....

Sounds like fun. What's your language skill set? Some of these countries will have lower levels of English speakers. We are all used to going to tourist areas in first-world countries, where English is common. In the East (and you are going to Eastern Europe), English is less common, and people at gas stations are not likely to speak English in that part of the world. Plus signs (In Ukraine, Moldova, and Belarus) are likely to be in Cyrillic, which is for most Americans like Greek. I took Russian in college, so I have rudimentary skills. I'd spend a short time working on Cyrillic, which is not as difficult as you might think. For instance, "рзсторан" is not "pek-to-pan", but is "restaurant".

Most traffic signs in Moldova have only pictures or the ubiquitous "STOP" sign. Most signs referring to towns, exits, and mileage are in the Latin alphabet (Moldovan/Romanian). You will see an occasional business sign in the Cyrillic alphabet in Chisinau.

However, in Transnistria region, I understand that Russian and Cyrillic alphabet dominate - though I have never been to Transnistria.

Just to point out, most of the road signs in Belarus are "duplicated" in Latin, so you won't get lost. Of course, if we speak of the main routes and cities. Like Minsk, Brest, Mogilev, etc

If you are planning to "camp" in this region, you should be prepared for serious rain. I spent several days in Lithuania last July, and while some days were nice, we hit a stretch of a few days where it rained hard, steadily, with few breaks. I live in a place well known for rain (Seattle) so I'm not easily washed out, but the storms we went through in Lithuania (and western Latvia) kicked my arse and left me hiding in the car. Being out in a tent in that weather would be utter misery.

It won't be drenching rain your whole time, but I'd expect to get at least some of that. I've read many reports from other travelers going to this region in mid-summer expecting nice warm, sunny weather who were drenched and frozen out. Just be ready for a variety of weather extremes.