I found this text about smoking on the RCI website.
Smoking in public areas is only permitted in designated smoking sections which vary by ship. Generally, smoking is permitted outdoors on only one side of the ship; and smoking is permitted on all private ocean front balconies.
Smoking is banned in all Royal Caribbean cabins but if you have a balcony you can smoke there. Smoking at the bar in the casino is o.k. and there is one other bar, the Aquarium Bar the last time I was on VOS (same class as EOS), and one side of the pool deck. Also, one side of the ship on the deck that has the outside promenade and in the cigar bar.
I cruised on EOS several times in the past and enjoyed it. I hope you do too.