none at all from the USSR to other Warsaw pact countries.
Not exactly true. My grandparents and parents generation travelled - not much, but on several occasions.
It was considered a prestigious thing to do. Also, an opportunity to make lots of money buying Czech/German/Polish goods and then reselling them back home.
You first had to come up with a reason for why you were going. Most often, these trips were linked to party exchanges, student delegations, scientific cooperation, or some kinda heavily chaperoned group tours. Through bribery and favors, you could get yourself "written into" some delegation.
After some Googling now, I found a blog article with numbers for internal and external Soviet tourism.
Internal Soviet Tourism: 100 million people annually. Main destinations: Sochi, Crimea, Lake Baikal, the Caucasus, and the Baltic States.
Purpose: Most trips organized through work, by the Trade Union.
External Soviet Tourism: 500-700k annually (1980s).
Main Destinations: Bulgaria (the lion's share), GDR, Czechoslovakia, Hungary, Poland, Romania.
What's curious is that Poland was low in the ranking, second from the bottom from Romania. Apparently, this was due to Solidarity and the overall complicated political climate. The Soviet government did not want citizens exposed to this.
Romania - surprisingly - simply had a bad reputation as an uninteresting and deeply unfriendly country. Caecescu's government did not particularly welcome Soviet tourists, and there was a huge language barrier. In addition, the author writes that Romanians came across as "aloof" and "deeply nationalistic" to Soviet tourists raised on the idea of Internationalism.
Albania left the Warsaw Pact in 1968 and was off limits to Soviets.
Yugoslavia was semi-accessible, but trips there were tightly controlled. The favorite destinations there were along the Adriatic coast.
The real Soviet "elite" could of course travel to places like New York and Geneva, as "members" of various UN delegations.
If you were some kind of untouchable star like Vysotsky, you could even live in Paris with your girlfriend.