I would suggest going to 300 win . Shots tend to me further out west at least in my hunting. In the 300 win would suggest 200 gr Hornady eld bullet has worked great for me. I tend to use swarovski scopes but really like leopold 3.5 x18 with red dot reticle.
Pack 3000 cubic inches
1. extra wool t shirt
2. extra pr socks
2.knife and sharpener
3. small saw
4.water and life straw 2 liter Hydration bladder gator aid mix.
5 couple sandwiches and 2 candy bars
5 thermos coffee survival blanket
6.phone and inreach by garmin
7. book
9. small tarp
10. Gun...
I have killed moose and going again in October. Shots not normally long but a lot of brush I would much prefer Aframe bullets. Shots are close and brushy
You say long range hunting . What do you plan to range with? The more power you have the better you can see in shadows. Thats where that big buck is going to lay. I would suggest you take a good light weight spotting scope or 15 power binos. You will be surprised how much more game you will see...
I had Lex Webernck build me a 4.5 lb rifle then added Talley rings and bases 30 oz scope . Mountain hunting I have found my back pack works best as rest.
I have the model 7 in 7mm08 and 65 cr I prefer the Creedmoor . When shooting recoil is less important than loud noise.Have her put in ear plugs then good set of hearing protection . By cutting noise kids will shoot much better. I have gone one step further and use silencer on my rifles.