I left a step down unit to come to PACU and I find it much less physically demanding. Yes, I am standing more, but do a lot less pulling up, turning, etc. my lower back rarely aches now. I also find it is easier to get helpers in PACU than it was on step down.
I suspect every facility has different call rules. At mine call is mandatory, but because we have a couple of overnight people it is weekends we have to take call. Ours is rotated. I am currently on the Sunday rotation, so I am on call one Sunday per month. Call is either 16 or 24 hours on Saturdays and Sundays. We are also scheduled a Saturday 8 hour shift once every 2 months. We pick the Sunday unless you are bottom of the list, in which case you get stuck with whatever is left. We can trade our call days. We have 1 hour to get to the hospital when we are called in.