Well, I am not sure that I am qualified to reply as we are still in the process. However, I do have to say that the decision has been pretty clear based on balancing what DS absolutely needed with practical considerations. This has meant choosing not to accelerate as fast as DS can ace a course, but only as far as it would have actually been harmful to not accelerate. As a result, DS is an incoming 6th grader who has been accelerated two years so scheduled for Geometry with 8th graders in the Fall. This means that DS will likely be taking either Linear Algebra or Differential Equations as a Junior or Senior even if he also takes the "sideways" option of Statistics as a Junior/Senior. Although Linear Algebra and Differential Equations are harder than Calculus, they are also natural progressions so not necessarily harder to ace.
Of course, in your DS' case, you may be talking about a more radical acceleration than we have chosen for my DS, but the same issues are present. Ultimately, I would say go with your gut. If everything has been so easy thus far, it makes more sense to stay on course unless/until your DS hits a wall. For what it is worth, I would go with your option #1 and accelerate rather than to work independently on EPGY, AOPS, etc. without acceleration. While I know that some people think highly of EPGY and AOPS, they are not accredited and there is the perception in some education circles that they are not sufficient in and of themselves. I am not knocking AOPS because I actually love alcumus but I wouldn't allow that to be DS' only credential for practical purposes.
