You're right, lots of good advice so far. Take this for what its worth.

True and time the action- You mentioned that you aren't in a hurry. That's important because "gunsmith time" and real world time are not always the same. That being said I talked with Kevin Rayhill at Stockade guns (308) 432-5114 the other day about having a time and true done on an action and his time line was very, very reasonable. I've dealt with Stockade in the past and they are very good about getting work out when they say they will. Better than any other smith I've dealt with. Will it make a huge difference? No way to know until its done. For a relatively small investment you have the insurance of knowing that everything is straight and true from the start. The timing may not have a huge affect on your accuracy but tit may make everything smoother, and easier to catch inconsistencies, which can really help in the long term.

For the barrel, talk to Jim at Northland Shooters Supply (763) 682-4296. He is very knowledgeable and carries barrels from the best manufacturers out here. I have a number of CBI barrels from him as well as Shilens and they are shooters. He will answer your questions, point you in the right direction and get you what you need. His recoil lug is worth the money.

As far as caliber- go with the 243. It is accurate, deadly and easy to load for. You can find ammo or components anywhere, lots of load data, no recoil to speak of and it is very versatile. When we lived in WY we had a 243 with one of Jim's barrels that we loaded with58/65gr bullets for pds and coyotes and 100gr bullets for mule deer. It was awesome for both and I wish we still had it.

Best of luck whatever you decide.