I remember what it was like dreaming up the perfect rifle for Alaska and the OP is in my opinion on a good track.
In the medium bores. [ 8mm to 375] all my quests were solved with the 375 Ruger Guide Gun/Rifle. ( Marlin beat Ruger to the Guide Gun moniker)
The M77 Mk2 stainless Hawkeye has all the bells and whistles on it . Out of the box , that we used to pay boat loads of money for.

The only thing it could use that it doesn't come with is a short Pic rail section for a light.
Buy the rifle . Buy a good scope. Spend all the gunsmith money on ammo and components.
With use the action will slick up so it slides like a hot knife thru butter.
Maybe invest in a few spare front sight blades in case one gets broke off when the rifle get dropped hard.

But. Having a custom 375 built is a grand thing!