Paul,
My friend has several M1903 bolts and parts for sale. Let me put you in touch with him for details. Send me your email address or phone number.
My email is: Johntravelerman1@hotmail.com
If you want to re-barrel to .25-06, .270, of 7mm-06, that would be the easiest and cheapest way to go. Both need no action work to feed properly.
All other shorter rounds would need some minor action work.
What's wrong with keeping it in the original caliber? If the receiver hasn't been drilled or tapped, and the barrel is good, your restoration would be a money-maker!
John