Recommend Uxmal over Chichen Itza in Progresso. Bus company that handles the pier transport runs it at 930 last we were there. Shorter trip, well excavated ruins, and far fewer people.
From Coz would never take a trip to mainland. Way too much ferry and bus time for ruins time. Ships sometimes offer Tulum and beach or snorkeling but travel time kills the latter and you still get short ruins.
Native to Chacchoban worked great for us and we got there well before big busses. Private guide for 6 people and pretty good ruins. Note pyramid stairs are steep and large steps.