At its most basic, Simple Foreknowledge suggests that God knows the future by watching time unfold from his timeless perspective of observation. In other words, God, unhampered by time, knows the future because he's seen the future. Though this would seem to cast God in the role of merely observing, it actually does not preclude him from making whatever interventions he would like to make. He can observe (as I would suggest he most generally does) and he can shepherd and influence whatsoever comes to pass in time.
Time itself is an aspect of creation. From the standpoint of that creation, God is both omnipresent and omnitemporal: from his standpoint, he just is. God is neither in time nor dependent upon it, anymore than God is in creation or dependent upon it (aseity). It seems to me, therefore, that his knowledge of creation cannot be dependent upon time, even though if there was no creation (nor the time that is an aspect of it), he would not then know it. Given that he did create, God knows his creation entirely (from stem to stern, from beginning to end) without being bound by the progression of time.
Now exactly what time is, is hard to say. We can measure it even though we cannot contain it. It's stamped into the warp and woof of everything, but doesn't seem to be anything at all. It is possible to see it as nothing but an arbitrary way to relate the sequential, but since everything is always in motion, sequence is fundamental to everything in creation.
As a consequence, our knowing of anything we have knowledge of is completely wrapped up in sequence and time. Line upon line, precept upon precept, evolving one concept from those derived before--this is the way we think and know. To project this creation-bound, time-bound construct upon God, however, would be a mistake. God knows differently than we know, he thinks differently than we think.
For God, knowing is neither time-bound nor time-dependent--if anything can be known, he simply knows it. He isn't waiting for prior steps to unfold, nor building line upon line, precept upon precept. He neither had to formulate a plan (though he has a plan) nor iterate various possibilities before he acted (is it even appropriate to speak of "before" with God?). There is nothing about God's knowing, within himself, that is a process at all.
It is beyond doubt that our template for knowing cannot be laid upon God in order to understand his knowing within himself. Even though God's interactions with our realm have a sequential quality to them (see Genesis 1 and God in the Moment ), they only do so from a perspective within creation, not God's perspective "outside". Past, present, and future only have meaning where they matter (i.e., in time), not where they form no barriers whatsoever. Though the effects of his acting and the experience of his knowing while in interaction with the time-bound has a sequential quality to it, God, in himself, knows in timelessness.
What this means is that God's knowledge of what is the future for us is not shackled to sequence. It's not the future for him, it just is. Therefore, any notion of our future being locked in, or determined for us if it is known by God is unfounded: any argument based upon that supposition a non-starter. We can act freely, and God can interact, even iteratively so, within time and not have to "adjust" his knowledge of all things, including the future, for that being so. He can cause a miracle, or answer a prayer within time, without having that action alter in the least his knowledge of all things.
He sees all at once, as it were, only we have to wait for time. As I perceive God's knowledge of the future, Simple Foreknowledge adequately describes the nature of such from a biblical perspective.