There is evidence that the events of Genesis took place but only if one believes the words of Jesus Christ in scripture. When answering a question about divorce, Christ gave this answer:
Mat 19:4 And He answered and said to them, "Have you not read that He who made them at the beginning 'MADE THEM MALE AND FEMALE,'
Mat 19:5 and said, 'FOR THIS REASON A MAN SHALL LEAVE HIS FATHER AND MOTHER AND BE JOINED TO HIS WIFE, AND THE TWO SHALL BECOME ONE FLESH' ?
So Christ himself, whom scripture teaches IS God, affirms that the creation account is valid. Or at least he never disavowed them. Other biblical figures affirm the creation account as true and accurate.
The speculative part is the "why" of certain things. They're speculative because scripture is silent on some matters.
As a believer, I think that the proper approach is to assume that these things are true and figure out where and how the physical and historical evidence fit into this truth.
The bible can not be considered evidence in logic any more than the book of Mormon or the Koran. You can say you believe it but that does not make it true. Science deals with objective measurable facts of existence. The base of knowledge of reason is existence. The base of knowledge of faith is belief without reason. The substance of that which is hoped for is a wish. Wishes are not absolutes. Feelings are not absolutes. Numbers of believers are not a substitute for evidence any more than the number of believers of a scientific theory if there is no evidence to support it. Existence is an absolute, facts are absolutes. Feelings are not. Arbitrary claims are not means of cognition.