Adam and Eve at their creation had knowledge of the original law of God. It was imprinted upon their hearts, and they were acquainted with the claims of law upon them. When they transgressed the law of God, and fell from their state of happy innocence, and became sinners, the future of the fallen race was not relieved by a single ray of hope. God pitied them and Christ devised the plan for their salvation by himself bearing the guilt. When the curse was pronounced upon the earth and upon man in connection with the curse was a promise that through Christ there was hope and pardon for the transgression of God's law. Although gloom and darkness hung, like the pall of death, over the future, yet in the promise of the Redeemer, the star of hope lighted up the dark future. The gospel was first preached to Adam by Christ. Adam and Eve felt sincere sorrow and repentance for their guilt. They believed the precious promise of God, and were saved from utter ruin. {RH, April 29, 1875 par. 4}

Paradise was lost to Adam and the curse was pronounced upon the earth because of the transgression of the Father's law, and death came because of sin. Adam found by sad experience that it was easier to transgress the commandments of God than to resist and press back the tide of moral wretchedness that was pressing in upon him. Those who lived before the flood were favored in having a knowledge of the law of God communicated to them by Adam who had conversed with God and angels in Eden. He lived among them nearly one thousand years, and by his teachings, example, and humble obedience to all God's requirements, exalted the law of God. He sought to turn his posterity from transgression to a life of obedience and faith in a Saviour to come. {RH, April 29, 1875 par. 5}

And as has been pointed out, the specif omission of something does not mean it is not true.
Then there's the issue of a specific mention of them avoiding utter ruin.

No, James, it is not speculation to speak of Adam in Heaven. We know he will be there. We also know William Miller will be there, and I think we have pretty solid evidence that Mrs. White will be there too.

Certainly, you are right, there are some things that are not revealed to us.

My attention was then called to William Miller. He looked perplexed and was bowed with anxiety and distress for his people. The company who had been united and loving in 1844 were losing their love, opposing one another, and falling into a cold, backslidden state. As he beheld this, grief wasted his strength. I saw leading men watching him, and fearing lest he should receive the third angel's message and the commandments of God. And as he would lean toward the light from heaven, these men would lay some plan to draw his mind away. A human influence was exerted to keep him in darkness and to retain his influence among those who opposed the truth. At length William Miller raised his voice against the light from heaven. He failed in not receiving the message which would have fully explained his disappointment and cast a light and glory on the past, which would have revived his exhausted energies, brightened his hope, and led him to glorify God. He leaned to human wisdom instead of divine, but being broken with arduous labor in his Master's cause and by age, he was not as accountable as those who kept him from the truth. They are responsible; the sin rests upon them. {EW 257.1}

If William Miller could have seen the light of the third message, many things which looked dark and mysterious to him would have been explained. But his brethren professed so deep love and interest for him, that he thought he could not tear away from them. His heart would incline toward the truth, and then he looked at his brethren; they opposed it. Could he tear away from those who had stood side by side with him in proclaiming the coming of Jesus? He thought they surely would not lead him astray. {EW 258.1}

God suffered him to fall under the power of Satan, the dominion of death, and hid him in the grave from those who were constantly drawing him from the truth. Moses erred as he was about to enter the Promised Land. So also, I saw that William Miller erred as he was soon to enter the heavenly Canaan, in suffering his influence to go against the truth. Others led him to this; others must account for it. But angels watch the precious dust of this servant of God, and he will come forth at the sound of the last trump. {EW 258.2}

Of course, the Bible was not written after Miller's time, so we could not expect the Bible to tell us this about him.

It's like God has given up on you and you begin to imagine your eyes were opened and you have become wiser than Daniel.

James,
What was Miller told not to do? In fact, you speak as if you do not know him. Have you read his writings? He never claimed to be a prophet. He was merely preaching the prophecies of the Bible. He did not have any prophecies to tell save those contained in the Bible itself.