So I'm gathering that everyone in this thread supporting him doing this, is either
A--single and lonely
B--single, lonely, and young
C--married way too young b/c of being knocked up, or just married young in general.
The people NOT for this are
A--the older generation that have been around longer
B--single by choice
C--single not by choice but smart enough to know it'll happen at the right time
Anyway. OP why are you asking for suggestions on how to propose? WE don't know your girl, YOU do, so why ask us? You know if she's quiet and shy, or if she would want it public, an audience, etc. You know what her hobbies and passions are. Tie them all together.
My exfiance proposed to me almost perfectly. In my favorite place, with my favorite animal, but there were people around. I myself would prefer privacy, then call/text/fb everyone I knew later. I want to enjoy the moment with HIM..not everyone else.