As long as he can get into the Schengen region, he can get to Belgium in a van without any paper trail. I'm not advocating illegally entering any eastern EU co

As long as he can get into the Schengen region, he can get to Belgium in a van without any paper trail. I'm not advocating illegally entering any eastern EU countries, nor suggesting that it is easy, but from a physics standpoint it doesn't occur to me as exceptionally impractical for a determined and resourceful actor with international support, considering the mountainous terrain of Hungary, Estonia, Latvia, etc.