How do you transition to the Army National Guard or Army Reserve as an Officer from Active Duty? Are there limitations for doing so?

You will owe 3-4 years active duty, based on scholarship, then you are eligible for Guard/Reserve or IRR for the remainder of the 8 year total service obligation.
There must be a valid officer vacancy to assess you, it will be possible to assess you into a position other than your basic branch, and you will need CCC for that new branch.
ID ARNG is pretty small, about 3,000, and the Army Reserve in Idaho is probably smaller than that, you will need to be flexible on branch for a position.

I was Guard my whole career and didn’t have to do it but we had many officers that started on Active Duty and they said it’s relatively painless. Contact the Nation Guard in the state you plan on living in and they can walk you through the process. You may have to do a branch transfer if you end up in a unit that is different than what your branch is. But Idaho is the home of the 116 Cav Bde and has one Armored Bn and one FA Bn in the state that I know of they also have an Engineer company (that’s where I started when I was in the Idaho Guard while in college). I’m not sure what other units they have but if you are in FA ARMOR or Engineers there will be slots available for you