These should be areas of focus for relatively new leaders (3 years or less experience):
1. Understand the BSA parameters. Constantly study the Guide to Safe Scouting, acquaint one's self with the Troop Leader Guidebook. Understanding what the is permissible or not is key. There is no help for an adult leader that haplessly blunders into forbidden territory.
2. Learn to use resources that measure conditions. For example, many flat foots head out Grayson Highlands & Mt. Rogers VA in the Spring for backpacking not understanding the relationship between altitude (4500-5500') and weather vs 400'. Many find themselves nearly freezing to death. There are resources that can help figure things out, such as Wunderground which used to have historic data on private weather stations in some places that are relevant to hikers. This may not be the case anymore, but the point being, be diligent.
Comprehending river flow data is another skill. Use resources such as this https://waterdata.usgs.gov/mo/nwis/rt to stay on top of conditions leading up to a trip. Have parameters (max safe flows for any given outing) in cfs flow established well ahead of the trip.
3. Take the time to enroll in First Aid, and more importantly Wilderness First Aid. Make sure the WFA class is legit. Our local council just had a fella offer an 8 hour WFA. Those who are in the know understand this is not legit.
WFA can/should inform folks how to run a tight ship, such as release form/health form management. Yes, I carry 4 pounds of health forms when backpacking.
There are a multitude of other online classes that are helpful provided BSA. If your unit love rivers, take some ACA classes.
An umbrella insurance policy won't bring someone back from the dead, or out of a wheelchair due to spinal injury. It is all about discipline, discipline, and discipline.
Thus far in 6 years, our Troop has had more issues with adult crisis than issues with the youth. Heart attacks, and diabetes related issues loom large on the adult side. On the youth side, a youth experienced moderate secondary complications stemming from a tick bit, and one incident due to not using water purification equipment properly....GI issues. My biggest fear is an adult leader dying of cardiac arrest in the woods.