Four Basic choices to cover NA w/Alaska in the mix:
.22 LR w/scope Bolt or semi auto
M
.223 Rem AR or maybe a bolt (I do like the AR for a SHTF)
.260 to .30 for the middle of the bunch stuff bolt w/scope my fav is a Rem 700 in 7mm RM (I actually cover this "spot" with three, .257R, 7mmRM and a .308) but there isn't one "perfect" pick, (some are a little much and some are a little short on one game or another) so this is a tough pick and a Ford vs Chevy kind of thing...you can't go wrong with a lot of the calibers in this slot I just believe that a 7mmRM will do more YMMV
At this end for one pick it has to be a .375 H&H but a .338WM, a .338-06, a .35Whelan all can work her as can a .45-70 And, my preference is a controlled feed Win 70 or Mauser cuz critters in this group see me as food...LOL.
Now, add a .357 or .44 or .45 revolver, a .22 handgun or some type, a .20ga and a .12 ga shotgun and you are getting somewhere near the essentials needed. You can build onto that...