I am also a single parent and debated whether to take my daughter on a cruise by myself. I came to the conclusion that it would be one of the best places to take her!! There was also a trip report from a single parent on the Trip report board but I can't seem to locate it. I linked an earlier thread to it but now I can't find it!!! It was GREAT.
With a cruise, you have the opportunity for "together" time and "alone time". From what I have read, the clubs and labs are wonderful and allows supervised care (that is enjoyable - not just a "sitter") for your daughter so you can have some adult time. There are so many activities you can do together, it would be fabulous. You have the best of all the worlds on the boat!!!!
Do it....it will be "Magic"al and/or "Wonder"ful I am sure!!
We are lucky to be going with a couple of other families from our gymnastics center, HOWEVER, we may go next year alone. I want to go on a 7 day cruise and we are only doing a three day this year...*pout*.....
Good luck on your decision, whatever you decide, HAVE FUN AND ENJOY YOUR TIME WITH YOUR DAUGHTER!