Bottom line, minimum equipment, reliable, ease of use under stress, able to survive primitive and combat abusive circumstances.
What do I go out and procure for on foot mobile comms for a citizen small unit infantry team for inter squad and checking in periodically with a home base system in the Appalachian Mtn range?
Keep it simple, rugged and primitive as possible.

In Mountains or other hilly terrain, 2M works best. The most rugged, yet inexpensive set I’m aware of is the Icom V80.
You’ll need a simple 2M set in your Base of Operations, AKA a Command Post. A single band Mobile is what’s needed:
You’ll need a good antenna. The roll-up J-poles work well, and are great for temporary setups, such as a hasty Patrol Base or longer-range needs while on patrol. For long term durability, you’ll need a more rigid antenna. Most J-poles or Groundplane antennas will fit the bill well. Feed them with LMR-240 and you’ll have no worries.