First off welcome to LRH!!
I would recommend shooting the rifle as to see how it shoots and then go from there. Some factory Rem 700 LSS rifles are scary accurate, some are not so much.
But before you put alot of money into the rifle, see what she does as is. Upgrades you can do range from simple proceedures like trigger jobs, lapping lugs if the headspace specs will allow it, recoil pad upgrades.
You can then step up to a bit more involved improvements like recutting the crown, pillar bedding the rifle, trigger upgrades and striker assembly upgrades.
Then at the extreme end of the improvements you would have rebarreling with a custom match grade barrel, receiver accurizing and muzzle brake
These proceedures will run from $15 to +$1000 so its wise to determine just exactly what the rifle has to offer you before spending the money. You may get lucky and have one of the really good shooters that come from Rem.
I am not a huge fan of Nikon optics but I will say they are quality scopes. I just prefer leupolds or top end Weavers. It should serve you well though. Getting long eye relief is a good idea with the RUM in a rifle of that weight.