i have worked in restaurants my whole life...there is nothing more tacky(and humiliating to the woman)then a staged proposal in a restaurant...i might suggest climbing together to the top of some near-by mountain and then proposing there.this would show your potential life partner that life is hard but if you work together you can climb any mountain.
ps. are you marrying her father?why do you need to impress him?sounds like you may need to resolve something there.
good luck and god-speed.