Traveling through Guatemala

I need help planning a trip through Guatemala, we plan on going by car from Bacalar, crossing Belize, to Flores. The idea is to stay 2 days in flores and visit Tikal, Crater Azul…. And then I get a little lost. We want to go to Guatemala City, Antigua and Atitlan, but we are unsure of driving +10hrs from Flores to GC, or we should make a night stop in Coban, do we need to take a ferry ?? We have 9 days total, before we need to go back to Mexico via Chiapas… or take the same road back to Bacalar/Chetumal area. We are experienced road travelers. We plan on doing this trip staring December 27th/28th so we will spending new years there, probably in Guatemala City or near by, do things open on January 1st?