There should be more to your decision to customize a rifle than your simply wanting a custom rifle. What is it about the M-70 that A) you don't like and B) would suit you better? Have a vision of what you want your rifle to be, and a vision of what it will be used for, before you start adding bells and whistles, that in the end might serve no purpose, or worse, make the rifle unusable.
You mentioned the trigger, but as said, a M-70 trigger is pretty easy to set up, and if you can adjust it to 3 pounds with no creep or over-travel, there is little to complain about. If you can't adjust the creep out of it, then replace it with a Timney.
You mention that you replaced the stock with a synthetic, you didn't say what type. If the new stock fits you all is well, but if it was me, I would have a fiberglass (not plastic) stock made up for my length of pull. The original stock refinished, bedded and cross bolted, cut to fit you, with a quality recoil pad installed could well be a better stock than a cheap synthetic. Regardless of the quality of the replacement stock, it should be bedded to the action. There is no such thing as a "drop in" even though they are often advertised that way. A good stock needs a high quality recoil pad that matches the stock and your tastes. If you want ###y, a high quality piece of walnut is the answer, but the cost of turning a walnut blank into a work of art is not for the faint of heart. I would change the factory slotted action screws to hex or Torx head, with pillars to prevent compressing the stock material. The front sling swivel on the radius of the stock keeps the swivel stud out of the way, and prevents recoil induced cut hands.
To my way of thinking a hunting rifle without a good set of irons is incomplete. Not everyone agrees however, nor does everyone see the advantage of a ghost ring and post arrangement. But if you do, you realize that the scope must be mounted in good quality QD rings, and lately there has been a pic on CGN of a neat ghost ring that is built into a scope base, naturally the rings must be QD. If the rifle is equipped with QD rings, consider having a stripper notch machined into the receiver. This is one of the features available on Brokman's custom M-70s, and a visit to his website might give you some additional ideas.
The scope should be chosen with the end use in mind. Big game is not hard to see at normal hunting ranges, so the choice of a 10X scope would suggest that the rifle will have uses beyond that of a big game rifle. I don't like the look of a physically big scopes on hunting rifles, particularly those with large objectives. The big scope is bulky and more prone to damage than a smaller scope, and the smaller scope can be mounted closer to the bore if the height of the comb allows for a low mounted scope. I prefer Leupold to all others, because they're the only ones that to my knowledge have a Canadian warranty center. Korth Agencies provide fast turn around times, and can do things like change reticles and turrets.
As tempting as a new barrel might be, I would only consider it if the rifle's accuracy was below par. In the field few can shoot up to a 2 MOA rifle, so spending money on a half minute barrel might not be the best use of your money. If you are considering a new barrel, my choice would either be from Ron Smith (Canadian) or Kreiger as I believe there are advantages to cut rifled barrels. Pay attention to the contour and length of the new barrel. Too heavy a contour will spoil the balance of the rifle, but the contour must be chosen with the finished length in mind.
No custom rifle is complete without refinishing. I would opt for a bake on finish in a color that suits your tastes. These coatings provide much better protection from the elements than blueing, and look as nice. They are resilient to rough handling, bug dope, and cleaning chemicals.
