Best scope mounting kit: A screw driver and an allen wrench.
Best bore sighting system: Prop your rifle on a bench rest. I use a cardboard box notched to fit the rifle. Remove the bolt. Place a target at 25 yards. Look through the bore. Adjust the rifle until the target is centered in the bore. Adjust the scope until the crosshairs are centered on the target. Shoot. Adjust the scope until the shots hit the center of the target. Back off to 100 yards and shoot. For a typical big game cartridge adjust the scope until you are hitting about 2" high at 100 yards.
If you have a lever action, pump or auto use a small mirror to look through the bore.
That's how my father taught me 50+ years ago and it's what I still do.
Works for me.