I'm not actually a single mom, but I feel like that's how my trips work. My last two trips have been me (26) and my 6yo sister. We don't get to spend much time together so our Disney trips are our own family vacations. We got to be together and have a lot of fun.
Not being a single mom, I can't say whether you need time alone, but I think I would agree more with MickeyMonstersMom who said, "the only advice I found for single parents was, "Bring another adult or get KinderCare... you need to take time for yourself." Whatever - it's a FAMILY vacation to me. We do almost everything together, and I just can't wait to share this with them." I found this advice a lot too and knew there was no way I would take "alone" time out of my vacation with my sister (or my kids if that was the case).
We ended up having a great time together and never worried about the outside world. My job didn't exist. Her school and fights with another of our sisters didn't exist. We didn't worry about anything except having fun together and just being together.
Our first trip together was my 4th trip over all and it was the best ever. I agree that it is addictive because we were back again in March, are taking our mom in December and are already trying to figure out if I can afford it for next year (besides 2 Disney trips this year, I'm also getting married and moving from the East Coast to the West Coast). No matter what, we will be back...just the two of us (and my kids if any should happen to come along)!
Have a great trip with your kids! I know you'll enjoy every minute of it!!!!