I suggest to make Advanced Work Benches purchase-able from the foremen. If you got the caps, why not allow it to be bought? Make it expensive like 500,000 caps or something like that (that's more expensive then the best base!) I mean, everyone pretty much crafts safely anyways, why not just let them do it in peace? When you give the money to the foremen, he could go with you to a base or ranger camp and there you could tell "I'd like you to upgrade this bench please." And ta-daaaa! 500k for a session of happiness. I like it.