To move in this direction is to consider matters "contrary to fact," that is to suppose God's will for history to be another from that which has been realized. Some things that "would have been" have been revealed to us (under some supposition of all-things-being-equal), though they are quite limited in number and scope. I'm thinking of a verse like Mt.11:23. But for the most part, it is speculative.
But it still seems reasonable to consider that there must have been a bona fide potential to the Covenant of Works. Typically, we speak of Adam's probation as holding forth the promise of a superior estate than the one in which he began. He would have been "confirmed" in holiness, and his ultimate (eschatological) situation might have been something like that which we know the angels of glory have. Their glory is also situated in the midst of conflict, as they battle on God's side against the powers of sin and evil unleashed in this world; but this is an artifact of the fallen world. In an unfallen creation and heaven, they would engage in their present duties without reference to such a conflict.
So, was Adam then looking for another heaven-and-earth? I don't think it would be sensible to think so, unless there were additional worlds in which he could fulfill his image-bearing, besides the one he was created and ordained to subdue. Was this world fully capable (as formed originally) to maximize that capacity with which he was endowed? We don't know.
