When we built the house in 2006, I put down a thin layer of crusher run (cheap stuff). Then it had rail road ballast which is a bit smaller than your 3" pieces. Despite the wining from all, I gave that about 5 months (Jan-May) to get packed in by traffic. Then I put down another thin layer of crusher run.
About a year later, another layer of crusher run. Then, this year, I put down some screened crusher run (3/4 and smaller). The driveway is in good shape. Only two downsides:
1) The 3/4 stuff likes to washboard, but when it's smooth it's better than just crusher run which has everything from 1.5 on down.
2) When you go to smooth it (I now use a land plane), you've got to be careful not to go so deep that you bring up the big stuff. It won't go back down.
So looks good there, and I think it's a good idea to let it settle in a bit before doing any next step, if those that use it can stand the rough ride.
Pete