You asked about armament, and have plenty of answers. Aside from the gamut of rifle choices, which your choice falls well within, there is other good information here. I’ll add a few comments of my own for your consideration.
To answer the questions you asked, it depends. Early on, I used a Ruger M77 in .270 and a fixed 4X; elk fell to that. Now for elk I use the same model rifle in either a 7mm Rem. mag or .338 Win. mag depending if I am expecting griz or not. They have worn Leupold VX III in either 1.75-6 or 2.5-8, but I prefer the 1.75-6. Nosler partitions and Swift A-frames respectively. These are closer to 9 pounds full up and loaded. My rifle stays in my hands when I am hunting. After a few days it just feels normal, when I return to work it feels weird not to have the rifle. The 7mm mag does a fine job on elk, and actually I think it is one of the best choices (but I am an old throwback and it is my pet rifle). On the other hand where griz are, especially in thick dark timber, the .338 mag is more comforting, and has the likelihood of dropping an elk closer to me, as long as I put a bullet in the right spot. Not having an animal running a long distance before expiring is preferable. That way maybe I can get to it before the bear does. I generally don’t take long shots, with the average well under 100 yards. BTW, dragging a dead animal through woods where griz are is leaving a clear scent trail indicating a reward at the end of the trail. Scary idea. Especially when you, as another hunter, blunder into that fresh, bloody drag trail. It makes you perk up and wonder if there is something large and furry following it in your direction.
How far, depends on terrain, how deep the snow, how ridiculously steep the footing, how bad the blowdown, how much elevation gain and loss, what I cut for tracks, what I see across a valley, what other hunters are doing. When you are in elk country, distance is not so much measured in miles as it is in hours - how long does it take to get to point A? Still-hunting is not a race; speed is not always your friend, it can blow out the elk you worked so hard to get to. In a less productive area, and when I knew less about elk, 8-13 miles per day was not unusual. Recent years, more like 6-8 in better country with more elk. Last year, not so much (3-4 max), but I was walking on two very recently replaced joints. I still got into elk, however. (I should listen carefully to that statement myself! Hmm.)
Now to questions you didn’t actually ask:
“Another consideration is that dropping an elk 5 miles from the truck will result in at least 4 trips out (maybe 5 with gear). 4 round trips, at 5 miles each way, is 40 miles... half of which is loaded down with a heavy pack. Depending on weather, this can be stretched out over a couple days, but a lot of folks don't fully understand how much work is in front of them when they pull the trigger.” Very good point here. Let me just say that if your camp is 4 miles from the truck, and you shoot your elk 3.5 miles downhill-uphill-and downhill from camp, well do the math. How many load/miles and days will it take you to get the meat and your camp out?
“As to mileage, I think you are spot on. I'd also add elevation to the equation.” Elevation is a multiplier to mileage, not just additive. Either up or down adds considerable strain on knees, thighs, and feet.
Finally somebody mentioned good, supportive, well broken in boots. Get them this year and use them all broken in next year.
340mag has had some real experience and has practical insights. While his innovative solution for a meat pack may not be everyone’s choice, it actually looks like a very practical solution. It is in effect what I use, which is an old REI/Kelty aluminum frame with a pack that has a single large compartment. I carry drum liners to line the pack (and for use as emergency shelter), and worry about game bags once back at the truck. That pack once carried out 125 pounds of boned out meat in one load without failing + emergency gear and rifle – I was younger then. My day pack will hold a boned quarter or backstraps and tenderloins on a first trip out so I don’t lose all the best meat to a scavenger before I return with the real pack. How you plan to get the meat out to the trailhead is a consideration, and should be thought out before you put an elk on the ground.
A handgun, well, maybe in some parts of Colorado where the risk of trouble is lower you may not want one while packing meat. I generally carried my rifle while packing in CO, mostly because I didn’t have an appropriate handgun yet. These days in grizzly country I never go back for meat without a gun and bear spray and caution and noise. If there are two of us, we may only carry a couple .44 mags and bear spray. Even with a rifle, handgun, and bear spray at hand, it can feel a little lonely gutting an elk without backup in that country, especially when you know the griz are in the immediate vicinity.
One other thing. I noted one comment about stripping down to minimum gear for the return to pack meat. Be careful about that. You would be wise to take minimal emergency gear such as lights, water, food, raingear, first aid, and a way to make fire. Things don't always go as planned. If you or your partner is hurt while cutting meat or packing, you may spend the night out. That is one place a handgun can make you feel better, even if it is a minimal solution to a bear coming in for your meat in the dark.
