Can I switch to National Guard from active duty Army while in AIT or afterwards?

Enjoy the "suck", do your best and live the lifestyle. The time served will be worth it. We learn life through our decisions and actions taken. If you have a negative attitude toward fulfilling your agreed upon obligation, you will have a though row to hoe. This could lead to your early termination of your contractual obligation prior to it's completion date. This in turn could lead to a lower characterization of discharge, and thus possibly some prejudice in the civilian sector that could affect certain benefits.

No. Once you have signed active duty and shipped out, you're locked in to AD for your contract length. When you're about six months out from ETS, you can start talking to the Guard if you would like to sign another contract after your AD time is complete.

Your best path in this decision in life is to just complete this contractual obligation. Your education benefits will vest far faster in AD than NG and by time you’ve jumped through all the hoops to switch to NG you’ll nearly be done anyway, while at the same time having to go into work everyday with everyone you’re trying to get out. Just play the game do what is required of you and a clean honorable DD214 will be a golden ticket in your future life.