Remember what the meaning of "free play" is. The kids are free to play with whatever I have set out for them and I am free to do what I want to do within reason. So if that means I am going to sit with a cup of tea and glance at a section of the morning newspaper that is what I do. It is important that while we are overseeing the children that we are not hovering over them all day or directing their play. Also there are times when it is ok to rethink the work we do after hours such as can you skip vacuuming some day and just clean the kitchen and bathroom. If all the kids are in diapers and no one is potty training do you even need to sanitize the bathroom every day - maybe just the sink from all the hand washing. My point is to find compromises that allow you to get the breaks you need. One of the reasons I stopped doing daily reports was because the only time to concentrate enough to do them properly was during quiet time which is also my quiet time-lunchtime.
One trick I found worked really well was that as soon as the last child was gone - go take a quick shower and change your clothes. Always did that when my own kids were little so that I wasn't the one spreading the germs from the daycare kids to my own. And I always felt so much recharged after the shower.