Yeah as somebody coming from former Czechoslovakia, it was hard for us to travel too, even in 80s. My parents were forbidden to travel to the sea to former Yugoslavia for example, since it was neutral country that one could use to escape to Austria. Heck, even travel to very much communist Poland nearby was very hard, special approvals from apparatchiks were required and those were only granted to regime-friendly folks. Not unlike current China for example.
But Soviet union from my late grandparents tales was different reality, they used chewing gums and other stuff we considered common as currency much more sought-after by locals than rubles. It makes sense regime didn't want for people tt discover massive discrepancies between various parts of eastern bloc. As whole world saw few years after, mighty soviet union was actually pretty fragile mosaic with pieces desperately wanting freedom from often horrible and incompetent central Russian management.
One of the reason why eastern part of EU is not so happy with uber-centralization in Brussel - we saw what level of inefficiency such approach brings.