George
First the Rem action is a great choice for any type of gun combo, provided the proper gunsmithing will be accomplished on it.
Your action should be trued, i.e. face the action face (where it contacts the barrel), face the lug beraing surface (where the bolt lugs rest when in the locked position).
Some gunsmiths will true the bolt too, face the front and rear of the lugs, and then lapp the mating surfaces of the action and bolt.
The barrel, I think you are referring to fire lapping, while a good method for factory barrels, it is not recommned for custom barrels.
Fire lapping if you are nto careful will increase your throat area and in most cases accuracy will decrease.
Hart, Lilja, Shilen, Pan-Nor, Douglas, Keriger, and a few other barrel maufactures are high quality barrels.
All have one comps at benchrest shoots and will perform when treated with correct cleaning methods excellently.
Next step would be a strong stock, some like syn some like wood, either one has been proven to be just as accurate as the other as long as proper bedding techniques have been applied.
Bedding; the part of the action that contacts the stock should be bedded with some sort of high shock resitant and chemical resitance compound and formed to the actions bottom side when placed in the stock. No preloaded conditions should exsist when doing this and compentent gunsmiths or stock workers can accomplish this without worry.
The barrel should be freefloated so that a folded busniess card can slide easily between the stock and barrel.
Some people have used piller bedding this is where two pillers of some sort of metal have been seated within the stock where the mounting screws for the action hold the action.
These pillers contact the action and give it a firm position bedding with some sort of compound is also recommended as well as pillers.
The bedding should not contact the sides or bottom of the recoil lug as this may interfere with accuracy.
Action screws should be torqued to a specific amount, some say between 50 to 65 in pounds, becareful when doing this as Rem action plates are aluminum and may crack.
The barrel once all work has been done to it should have a nice crown with a 45 degree chamfer between the bore and the crown surface and should be concentric and without knicks or scratches.
What ever contour you chose it should be to your likeing when you receive this rifle.
Triggers;
Shilen, Timney, Jewell, Canjar, and a few others are out their, Jewell imho is the best with canjar coming in second because of their dual stage option allowing you to use it as a hunting rifle and as a benchrest rifle changeing the trigger pull to less when punching paper.
Scope bases should be of high quality, Leupold, Badger Ordnance, IOR Valdada. They should sit without any force in full contact with the action. Once the scope rings and bases have been placed on you shoudl lapp the scope rings so that they fit the scope to be used as to not put any preloaded force on teh scope possibly damaging it or affecting accuracy.
The stock
McMillian if you can get one within a resoanble time frame, Elk Ridge, H&S precision and many mroe are out their.
Just depends on your liking once again.
Handloads in many cases will net you the best possible accuracy from your new rifle.
Barrel break in should be followed as per manufactures recommendations.
Good luck with your new project.
Dave