spaniel
I totally agree with your thoughts of taking the 300 especially for elk. I drew a late elk hunt permit here in Idaho last season (it was a rifle hunt), but I decided I was going to hunt with a ML a 50 Rem 700ML... More than one day I saw elk but at a greater range than I was willing to try with the ML... Bout the middle of the season - I was getting a little frustrated so out came the Tikka 300 win mag... range was not going to be problem any longer. Dusted it off, cleaned the glass and loaded it up... but then the next morning I would convience myself - I am going to try the ML one more day... then I decided I would keep ML until Dec. 25 - then for sure switch to the 300... Dec 17 I finally got one in respectible range... poppedit with a .458/300 grain Nosler at 176 yards -I was tired of waiting for really close shot.
I am thinking for you hunt with the 300 till you take your elk - pass on any muley less it isa monster - till you take the elk - then once the elk is out of the way then go to the ML for muleys... I am not thinking of packing both at the same time.... But all of this ML hunting depends on terrain... if you out in the Montana desert - might not be much opportunity for the ML in a limited time period.
But I would still take both... ask your contact about hunting with the ML... if he is a hunter he should be able to give you a good thought or two about where you would be hunting...
Biggest thing is to have fun on the trip...