This topic's been on here quite a few times before. As one of the first answers stated, no one's going to win here. There are some basics here. About 99.9999999999% of the gassers out there do not have air bag suspension. So, when prepping to leave, they do not have to start up, just to air up the suspension.
On the other side of the coin, there's the Diesel units. About 99.999% of them DO HAVE AIR BAG SUSPENSION. And, at least about 99.99% of them empty the bags for camping. So, what that means is, when it comes time for leaving, they must AIR UP THE AIR BAGS, in order to have suspension. And, the engines air compressor is the component that does that.
Based on a few variables here, on the average, from dead empty air bags, to the time the system is filled and, the compressor governor cuts out, is "on the average" around 2-4 minutes, plus or minus.
Now, different folks have different procedures for prepping to leave a camp site. And some, take a prescribed amount of time, whether they need to or not, couldn't be changed if you held a gun to their head.
We have D/P and, there are times when I like to get a real, I MEAN REAL early head start, as in around MIDNIGHT!! We have the procedure down to a science. EVERYTHING is put away in the evening before departure. There is nothing out. Even the main slide is already in. All I have to do is, start the engine, hit the "Store" button on the HWH pad and, based on normal idling, it will take approximately two minutes for the jacks to be completely raised and, the bags to be completely full. At that point, we both pull out of the site.
We will hook up, coach to toad, out and away from camp some place so as to not bother anyone while doing this process. We know that most folks do not like to be disturbed during their sleep and, we try to accommodate that the very best we can.
There's even a time or two that, if circumstances prevail, we'll pull out of the campground in the early evening, around maybe 6:00-8:00 at night and, head to a local Walmart or Kmart to get a couple hours of sleep before the midnight departure. That way we don't disturb ANYBODY when firing up the big CAT at midnight.
So, it's pretty much a matter of common sense. If you own a pusher and, need to depart camp at the weeeeee hours of the morning, do be considerate, think about your fellow campers who maybe drove a long way the day before and could really use a good nights sleep, maybe even alter your normal departure procedure (i.e. hook up the toad out on the road someplace instead of letting the engine idle in the coach while you fumble around with all the components in the dark, right nest to folks trying to sleep).
It's obvious that you cannot air up suspension, bring up hydraulic Jack leveling systems, bring some slides in, WITHOUT POWER. You need to do what you need to do. Just be a bit thoughtful for those around you.
Scott