As far as having the rifle worked on I pretty much agree with the idea of waiting till you have the $ then do it all at once. Maybe the trigger now since that is easy, but if you factory trigger that has worked by a smith is good and can be set to #3 or less I would wait for that to.
Thing is your rifle may be just fine to get you to 500 yards, many factory rifles are. The only comment I have about the "oh my gosh" 800 yard shot is; don't go there until you are proficient at 800. Then you are an 800 yard shooter, not an 800 yard poke and hope.
I suggest you spend your money on your optics first. Rail base, good rings, the best scope you can possibly afford...... then there are rangefinders, binos etc if you don't have already.
Good optics can be great help on a so-so factory rifle..... but too often I see or hear of those who spend all their money on having a custom rifle
built and put a sub-par optics system on. You would not build a great full size 4X4 truck with big mudders and such then put a tiny 4 cyl motor in it would you?