Hey Pete, I asked a few guys this question also - both were recent OCS grads as prior E's also. They said that they drove and were able to negotiate orders and (some) leave in between OCS and their next station. They were both going to API for aviation, so it was not a PCS move and they weren't paid, but they did have adequate time to drive and pick up their families and so forth. Another FINSEL guy also told me that he has spoken with some order writers and that initial orders are only TO OCS, then you can negotiate from there and if you drive it will be much easier or they will buy you a plane ticket straight to where youre going to - and they will buy it during your Candio phase. I hope this helps a little - but try reaching out to some guys in the threads from your designator - like the API or SWO schools. Those guys will likely have some great info, but may not be reading these threads.
Best of luck and I hope to see you guys there!
Jake