It depends on a lot of things...the availability of appropriate military transportation being among them.
The bodies are first flown to Ramstein AB, Germany, and from there they are returned to the military mortuary at Dover AFB, DE. The process would usually take place within a few days, but that is not guaranteed.
A young soldier from this area was killed last winter and I seem to recall it was about 10 days from the family being informed until the funeral took place.
BTW...if you have the opportunity to see the HBO movie Taking Chance, you will see the detailed steps of processing combat casualties.