I think you could probably name your price within reason. Doubt its that easy to find someone to do it.
Depends on how long it takes , between 2 am and 7 am or 5 hours work ? wfp ? how easy is it going to be to see what you are cleaning ?
A lot of variables but I'd want at least my day rate if it were to be 4 hours +, and take the rest of day off.
In the past I've got up at silly o clock in the summer to clean shops and offices. I've enjoyed the early quiet hours unhindered by traffic and pedestrians but maybe thats just me !