Originally Posted by
bankops
If I was going to do such a trip I would take the Paris-Moscow train from Warsaw to Moscow. Then fly up to St Petersburg and take the ferry or train to Helsinki and a ferry to Tallinn. Then bus or train between Baltics and to Poland. I would NOT suggest driving a rental can any distance in Belarus, Russia or Ukraine! You will damage the car and end up paying for it.
Taking the Paris-Moscow or even Nice-Moscow train is indeed a great idea. HOWEVER, this requires getting both Belarusian and Russian visas and there have been multiple reports of Russian border guards not allowing third country nationals to cross Belarusian-Russian border. They claim that it is not an international border and they have no capacity to check the validity of Russian visas at that border. I would strongly advise anyone who s not Russian or Belarusian to not try to cross that border on land even with proper travel documentation.