I'm willing to travel to other countries more -- means u want to travel more often than it is . Im willing to travel more to other countries . more travelling I'm willing to travel to more countries. -- means u want to go to more countries

They actually have different meanings . the first means u want to do the action of traveling more . but the second one means u want to visit new countries that u haven't traveled to , yet .

Well the second one sounds more natural, if you say any of those sentences to a english speaker they will get your meaning. When you use quantifiers usually you put them next to the action example: eat more, exercise less. "I want to eat vegetables more" and "i want to eat more vegetables" both can be understood but the second one is more correct. https://learnenglish.britishcouncil.org/en/english-grammar/determiners-and-quantifiers/quantifiers

The ideal way would be, "I'm willing to travel more to other countries." so a mix of both. Hope this helped.