In most cases Journeyman Level is equivalent to E-5 as far as training and responsibility go. E-2 is trainee and E-3/4 is Apprentice. In the AF that can change slightly because you can complete upgrade training to the next level prior to actually being promoted but that's about the standard.
Your IET will only get you up to speed as an Apprentice for those civilians jobs that have those levels.
By all means find the job that interests you the most. If you want to go corrections/LE in the civilian world you can do that regardless of MOS/AFSC. Most departments just like to military service (and actually I know of a few that prefer to not have to "untrain" MPs).
Feel free to PM myself or ANGfireman regarding the guard if you have any questions about what it's like for families or those actually serving. He may have some insight into the MIARNG from previous experience that I obviously don't. (Poor man has been Navy, Army and Air Force in his 16 years
ETA: "Critical MOS" in the Army = guaranteed deployment on Title 10 orders. If that's something you want to do, that's great. My humble suggestion is find the kind of job you want and see what your goals are then compare what's available across the board and talk to a BUNCH of people. One branch is better than another, just different in how they handle things.