1. What is the law about consuming alcohol while carrying?
It would appear to only apply to concealed carry:
2. What is considered "plain view" for vehicle carry?18-3302B. Carrying concealed weapons under the influence of alcohol or drugs. (1) It shall be unlawful for any person to carry a concealed weapon on or about his person when intoxicated or under the influence of an intoxicating drink or drug. Any violation of the provisions of this section shall be a misdemeanor.(2) In addition to any other penalty, any person who enters a plea of guilty, who is found guilty or who is convicted of a violation of subsection (1) of this section when such violation occurs on a college or university campus shall have any and all licenses issued pursuant to section 18-3302, 18-3302H or 18-3302K, Idaho Code, revoked for a period of three (3) years and such person shall be ineligible to obtain or renew any such license or use any other license recognized by this state for the same period.
First, do you have a permit/license from any other state? "Plain view" is a moot point if you do because Idaho recognizes all other states' permits/licenses. Otherwise, this is the Idaho code for inside the vehicle:
However, notice that the prohibition is only for concealed "on or about his person". Also notice that the license issued is "a license to the person to carry a weapon concealed on his person within this state." So, it would seem, Idaho is only concerned with weapons concealed on or about the person.(9) While in any motor vehicle, inside the limits or confines of any city, a person shall not carry a concealed weapon on or about his person without a license to carry a concealed weapon. This shall not apply to any firearm located in plain view whether it is loaded or unloaded. A firearm may be concealed legally in a motor vehicle so long as the weapon is disassembled or unloaded.
3. What are some of the things to be aware of while OC in Idaho (eg police encounters, businesses, general public)?
My limited experience in Idaho has been nothing more to be aware of than in Washington.
4. Can you carry into a bar? I know you can't in Washington but I've not read the Idaho codes.
Bars are not prohibited in Idaho.