The ALICE pack and gear were not standardized until AFTER Vietnam, FWIW.
From what I know, most LRRP'S, SF, SOG etc tried to use "indigenous rucksacks". The issue rucksack was very painful. ALICE ruck ain't much better. :gunman:
As for the rangers, the Special Forces in the current pack work just fine. The rangers appeared in Vietnam by proclamation! They just renamed all the Division, and Corps LRRP companies to Ranger Companies! Same guys, same gear (some wore black berets), new name.
You mght look into different camo for recon marines. Most pics I've seen, they are either in Tiger Stripes or a camo that "kinda" looks like the current woodland pattern.
Oh Yeah, A real Tiger would be cool. They ATE a few recon guys!
True story. No doubt a few NVA too ;D
My 2.5 cents