Where can I find out more information about the Active Guard Reserve and what it is like for a 91B?

Reserve AGRs work full-time for the Reserves and can be PCSd to any place they need your MOS. NG AGRs work for the state they're assigned to and can be moved within the state. Most 91B AGRs are either training or readiness NCOs on the full time side. Taking care of the day-to-day operations of their units, planning training, scheduling schools for their soldiers, handling pay, etc.

As MTOE's for every unit are different, it will depend on the type of unit, their OPTEMPO, are they close to a supporting full time maintenance site. You can expect to spend 1/4 to 1/3 on mandatory Army stuff or more on a weekend. Maintenance will vary, most of your unit can't fill out a 5988E or 2404 properly. Flip side, when you go tot he field you stay busy. not a lot down time. Avoid aviation units unless you like watching flight mechanics sit on their tail sections, while you pull KP, Guard Duty, and every other ash & trash detail.

I'm currently a 91B and a part of the AGR program. Pm me if you have questions.

There are few AGR positions for 91B as Readiness NCO/Unit Administrator for maintenance units.

There are thousands of federal jobs for 91Bs to work as a dual status federal technician in FMSs, usually at or close to where their drilling unit is.
Those can be found at https://www.usajobs.gov/

Jacob have you looked at https://www.usar.army.mil/AGR/ or contact [login to see] which is the number on the link. I was Active Duty for almost 9 years then went into the Reserves and applied for AGR after being there for 5 years. I will tell you to be prepared to do many other duties on top of your job as a 91 series if you do become AGR, it can be rewarding and challenging. Good Luck.
Also here are the Eligibility Requirements https://www.hrc.army.mil/Enlisted/AGR%20Eligibility%20Requirements