.30-06 is fine. Lots of elk have been killed by .270's out here. Range = know your gun and it's drop off plus how good of a shot you are.
Elk hunting is vastly different from deer in that you need to cover a lot of ground to find the animals. Once you find them STAY on them. I would suggest scouting of course to get an idea for opening day and for opening day wear clothing/boots that you can walk miles in. Being mega quiet while covering ground is not nearly as important as when deer hunting. Many times you will smell the elk or hear them before you see them.
A bugle is not needed since your hunting cows and bugling is overrated these days. The one thing bulging could accomplish is tell you where the elk are from a long ways off. However I don't know when your hunting. If it's august/september bulls will be with the cows and either getting ready or rutting. If you do bugle you want to sound like a juvenile bull so every bull in the woods will be thinking about whipping ur butt and more bulls will respond. Without going into detail bugling is not the rip roaring guarantee that it used to be (Sort of like honkers and 747's)
I would suggest getting a few cow diaphrams and practicing with those so you can "cow call" and also one of these
The hoochie-mama is really easy to use. When your trying to find elk or stalking them carry it ready to use. In the event you break a loud branch or elk sense your presence hit the hoochie mama and wait. Many times (if not winded or directly sighted) they will figure your another elk and go back to normal activity shortly. If you find a herd of elk or animals cow calling can bring in other cows as they are very curious. This is how my dad got his elk bowhunting last fall. We parked the truck and moved off and immediately smelled elk. After setting up and calling for about 10 mins a young cow got real curious and came trotting to us. End of story = dead elk.
I don't check the forums often but if you have any more questions feel free to pm me and maybe I can help.
-lewis