I have done laundry at 2am many times. When coming back after Hoopla!!
I always take my shower at night, so I bring my laundry with me. I drop it in the wash, head for the shower, then when I'm done with the shower, I drop the clothes in the dryer. I go back to the campsite, tidy up, check email, then go get my dry clothes. I've found it costs me less to do laundry every day or every couple of days because a small load takes less time in the dryer. No need for $4 in the dryer.