Second Day Suggestions? (Don't hate me for asking this question again)

Hi all -

I have done a lot of searching through old posts and I'm just not finding many suggestions for different second day activities. We are scheduled to have two full long days in port in August. My party of 4 adults has said that they would like to cover Havana in one day and then head out to something different for the second day. It seems like the driving time to the other possible areas are really long... I'm wondering if it's worth it to spend 4 - 6 hours roundtrip in travel time? I've contacted the most commonly mentioned tour guides from this board and I've only received information back on the Day 1 Havana tours. I'd like some honest feedback as to whether it makes sense to try to go further and see more of the country on that second day -- or should we just dig deeper in Havana? And does anyone have any specific suggestions of tours or guides who would offer the kind of experience we'd like to find for that second day?

Thanks!

Lisa D