I don’t know. I had to apply for visas at embassies for like 20 of those in a row, around $150 USd each.

One of the world's most active overland travel scenes in the 1990s and early millennium was in the former USSR and Eastern Europe. These travelers had relatively weak passports, but they started with the countries that would let them in, and then they eventually used that travel experience to visit more discriminating countries (those are more likely to issue a visa if they see you have a passport full of stamps yet always went back home). This is why so much of the travel-book industry about overlanding far-flung countries is in Polish or Russian, not English. There were -- and still are -- organized clubs to help people out with this. Where there is a will, there is a way.