Don't put down the roadbase and leave it without compacting it (don't want it to soak up rain).Once you compact it you can leave it for a while (assuming there won't be activity on it). I would not put down the sand until you are going to be laying the stone(day before is OK).

sand will take all of 3 and a half minutes to put down so don't consider it necessarily a step on its own. Its the grading of the sand that may take a little while (and some expertise) and that needs to be done just before you are ready to lay your stone.