I've had 3 LOOOOOOOOOOOOOOOOOONG prodomal labours. (1-2 weeks!)
But once labour proper kicks in - it's only 3 or so hours until babe is in my arms - all 3 born at home. My body just takes a while for everything to get where it has to be for the LO to emerge.

#1 and #3 were born at 40w+13d and #2 at 40w+7d or so. With #1 I did the standard non-invasive things - curries, nipple stimulation, etc. Nothing speeded it up. With #2 I thought about what was stopping labour and dealt with my fears. With #3 I did the non-invasives - walking, nipple stimulation, etc. and then MW said Blue and Black Cohosh and Castor Oil as I was approaching 42 w and she was not comfortable. Reluctantly I did the Cohosh (nothing!) and then the Castor Oil - and then had DD and lots of diarhea! ICK!
Good luck!