You didn't mention what year your Montana was, but this repair guide covers the 1999 model as well as earlier Transports, and the engine should be pretty much the same still for a while after that.
http://www.autozone.com/az/cds/en_us/0900823d/80/1b/e6/4e/0900823d801be64e/repairInfoPages.htm
As far as the push rods, if you do have to take them out their position should be kept track of so that they can be returned to the same spot, not just Intakes vs Exhausts.
Can't really find anything on the coil pack, except for an alternate location up by the front end of the motor, but I have seen what you're talking about, and the bracket is usually mounted to the cylinder head on the back side.
One other tip is that you could try to rotate the engine. The Lumina cars had this feature so you could change the spark plugs on the back side, and this vehicle is virtually identical in the front end. You can find that described here;
http://www.autozone.com/az/cds/en_us/0900823d/80/0e/cd/9f/0900823d800ecd9f/repairInfoPages.htm
As far as "tool #J 41131" it's just a nylon strap with hooks on the end like you can find at any hardware store.
http://gsi.xw.gm.com/image_en_us/gif/000/000/401/401357.gif
P.S. Oh yeah, it's the gaskets not the Dex-Cool that's the problem. Go with the highest quality FelPro gasket for replacement.
