Hey Del, I've never worked with saplings, but with most woods, you can work them down to near bow diminsions and they can cure alot quicker. Just leave the limbs and tips a bit wider to minimize warpage. A white wood stave can be worked after about 3 months if it is stored in a dry area, but if you work it down to smaller dimensions, you can work on it after about 3 weeks.
I take white woods in the summer and yeller woods in the dead of winter. That being said, take them when ya can get them.
Hope that helps a little. Keep us informed on your adventure.....Terry