The app BikeRoute is really simple (needs more development) but basically will let you input a start address (frustratingly, won't use GPS to find current location) and an end address, create an unadjustable route, and then use voice output to give you turn by turn directions. It is the only turn by turn app I know of that takes into account bike routes.

The app MapDroyd will download the vector openstreetmaps data for offline use. It doesn't do directions, but downloading the data for the areas you're going to could be a good idea for areas out of service.

You can email yourself routes from google routes and use car navigation if you aren't using any bicycling-specific infrastructure. If you are, you can just keep the route open in google maps and just check it every now and again.