Thanks for your reply. I know what Ranger and Ranger school is.
Then you are aware the the only thing assignment to the Ranger Regiment has to do with Ranger School is that the regiment runs the school. Being assigned to the regiment isn't a requirement to attend the Ranger course nor is graduation from such a requirement for assignment to the regiment.
The actual benefit is a bonus to Stamina rolls to keep going when marching, exposed to extreme conditions, etc. That's not a requirement of serving in special operations units. Swedes and their neighbors might just call that Tuesday. Or the 10th Mountain or NTC OPFOR or Marine Mountain Warfare graduates (or 2nd MARDIV veterans) or....
As for replacing Ranger with Redleg, what about Vehicle Gunner or Forward Observer? A better option is really a "choose one" entry on the random table, perhaps with it limited to the a specialty from the listed skills.
EDIT: Come to think of it, I really like that. Change 6 on every career specialty table to "choose one" limited to specialties of one of the career's listed skills. This will require some reordering of the listed specialties to keep non-career skill ones possible (replace Melee with Scout on the Police Officer career, for example), but it will allow more varied characters.