anyone mounted a ROOF A/C on their sprinter?

The roof is where upfitters, commercial applications as well as RVs, usually put it. All you need is a 14-inch square hole and 120V 20A power connection (or a bit less for less than 13,000 BTU/hr. Assuming, of course, you mean to install a RV air conditioner, not some one designed for another application.

It was very straightforward. Cut the pre-determined hole, put the air conditioner in place and seal it up.

Nothing to it.

rent scofolling.

Well. I have heard some use long extension ladder with 2 people. 1 on top and 1 on bottom to guide. These are rednecks ideas. I thought of on an overpass one time but chickened out. Best probably be an barn or such to safely raised around 150 lbs. You guys on here are reminding me of younger days... Ouch! BTW, this was for an RV. Still, need to lift that thing.