It should be fairly simple, provided the barrel isn't larger at the receiver ring than a standard barrel.  I use an old pipe vise with thick aluminum shims over the barrel to prevent marring.  Then a wrench that tightens over the receiver, again with aluminum shims.  A barrel with a diameter larger than the original has to be seated to the receiver, and the face of US receivers are often not square.

Just a couple of added thoughts. I am not a gun smith and can not legally take in gun smith work. It is legal for a non gun smith to work on someone else's gun if it never leaves the sight of the owner, thus the offer for you to walk in here with it.
  If you do not have access to a milling machine or the skills to make clamps like those described in that thread, it would be easier to take it to a gunsmith that has already worked on Krags. Screwing the barrel off, cleaning the threads and tightening the barrel would likely take less than an hour. If the barrel lines up so the sight is centered, the extractor slot is aligned, and head space is correct, I do not see where that would cost too much more than $50.00. From what I have been hearing here, most likely those 3 things will be OK. If not you will probably need the gun smith's help to straighten things up.
One more thought if you have access to a heavy vice bolted down to something very substantial I could lend you my clamps. On the "HowTo sporterize" thread there are photos of the vice and milling machine I used as well as the clamps.

There are easy ways to check the head space without the usual gauges.