Hey Sara, chin up, 100% effacement is actually WONDERFUL. I think because you are already completely effaced, you will go very quickly. When I got to the birth center in labor with Jackson, I was 100% effaced, 3 cm's dilated, with his head at "0" station. Almost exactly four hours later, he was born: 8 lbs, 21 inches long. So I hope the fact you are so "ripe" as they say, lol, is a good omen for you and that your mom will be able to remain long enough for the birth.
Some "natural" inducers I've read about or heard of:
1.) Fresh pineapple
2.) Sex (although the prostaglandins in semen really serve mostly to efface--something you've already accomplished!
3.) black cohosh
4.) nipple stimulation (causes your body to release oxytocin, which in turn stimulates uterine contractions)
Good luck,
Rebekah