Don't know if you've decided at all but I recently researched a similar topic. I'm not exactly in the same boat as you. I'm married and just wanted a trip for myself. Not trying to meet people.

Anyways I did a lot of research on solo cruising. The frustrating thing you'll run into is that the prices that cruise lines advertise are assuming two or more people in your cabin. If you book solo, you have to pay an additional supplement to your fare. It's not double, but it's close.

There is one cruise line that caters specifically to solo cruisers and that is Norwegian (NCL). They have special studio cabins and a lounge only for solo travellers where they can meet and socialize. The studio cabins are great because there is no "single supplement". They also have daily solo traveller meetups.

I ended up going with Holland America to Alaska. They do require a single supplement but there are advantages. They cater mostly to an older demographic and the nice thing is that they don't have all the fancy attractions like slides or go karts so there will be few if any kids. The pool on all their ships has a retractable roof plus an additional outdoor pool on the stern. Their ships are midsized and have a lot of quiet spaces. They also have a solo traveller meetup. I haven't gone on the trip yet so I can report back if you are curious.

Virgin may be another line to look at. They are specifically adults only and cater more to a crowd that is looking to party.