USA is an amazing country for roundtrips! This country offers an endless amount of fantastic national parks, stunning amusement parks, mountains, oceans and lovely small cities as well as fall-in-love-cities like New York and San Fransisco.
California is so much of everything. The climate is perfect, the coast along Big Sur stunning beautiful, the granite mountains in Yosemite a dream. Not to mention the lovely citis San Fransisco and Carmel.