The time it takes to get there depends on how much trouble your character runs into, but in general, distance between Coba and Tikal is about three days' time, five days from Coba to Kiichpan, and eight from Coba to Coatepec. Clear across the continent would be something like ten days or so. Bearing in mind the effects of the incense and the need to probably stop off in cities along the way, most trips wind up taking longer than that.