CruiseMark,
We don't drink either. We asked to have all unwanted items removed from our fridge so we had room for what we wanted in it. They kept us stocked with water and a few sodas that we did llike.
I am also an avid photographer. When able I would wander into town without the group to focus on my photos. Often my spouse would find a local gym and while he worked out, I would take photos. You can, as others have said, easily wander a bit on your own with a tour group but be mindful of time. I can recall a couple times where our entire group was held up because we had several people on our tour that had zero consideration for others. Let your tour guide know what you are doing or make sure you know where the group is meeting up and when,
My husband is not a fan of group dining either. I don't care either way. On our Vietnam river cruise (can't recommend enough if you love photography) we met two lovely couples who were traveling together ... that adopted us . We did often times have breakfast alone at a two seat table just because we never came down at the same time. Dinners we usually met up and sat together. 3 years later we are actually still friends with them. If you aren't comfortable with something, talk to the crew...they will take care of you.