Definitely do not go with PROM, without knowing precisely what your midwife's approach is regarding how long she considers it safe to have ruptured membranes. Some are okay with 12 hours, some 24, some longer, but this is a big gamble, I think, in terms of if contractions do not start, then you're on your way to lots more interventions.
I second the suggestions of sex, and acupuncture/pressure. Walking has been shown to not be an actual inducer of labor, but I think the mind is a powerful thing, so if you believe it, then it might help.
Ditto with spicy foods.
I would not go with castor oil, personally, because it can cause severe cramping and great discomfort, from a digestive perspective. Not something that's fun to deal with, plus -- can't it affect the baby's bowels as well? I wouldn't risk it.
I would look into herbal aids for sure though, if your m/w is comfortable using those, and would consider having my membranes stripped. But the baby will not come until s/he's ready, even with membranes being stripped.
If you're 11 days past your EDD, I'd wait to do anything for a few more days, if you can stand it. If you're uncomfortable with unnatural methods of induction (pitocin, etc.,) then you can simply not show up on Saturday. It's your body. Your baby.
Good luck, mama.