The most helpful fundamental question raised concerns whether I am over-confident in thinking I know what ancient Israelites thought about the physical structure of the cosmos. This is a tricky issue. It is the case that there is a lot that we cannot be sure about regarding ancient biblical cosmologies. All we have are the texts that we have and we cannot be sure that they represented the views of everyone. Furthermore, we cannot always decipher the meanings of some of the texts, which can be infuriatingly obscure. Other texts are poetic and it is somewhat unclear how literally to take the imagery. (A point Peter makes well.) It is quite likely, given the historical and cultural gap between the Bible and now, that here and there in the book I have over-interpreted this or that image. Nevertheless, I don't think that things are so unclear that we must simply fall back into a global agnosticism about biblical cosmology. I still think that the overall shape of the world-view is clear enough and is as set forth in the book. I tried to detail the case for it (and my case is not simply mine, but that of the majority of OT scholars, so if I err on this score then so does most everyone else).
i) We have more than texts. Modern readers share the same basic physical world as ancient readers. Of course, the constituency for Parry's book is usually urbanites whose experience of the world is mediated by layers of modern technology. Therefore, it takes some effort on the part of a modern reader to imagine human life in more direct communion with nature in the raw. Mind you, even now it's not that hard to put modern civilization behind you. Just drive to a national park. Go hiking in the wilderness. It's a question of how much civilization you wish to take along with you or leave behind.
ii) This applies, mutatis mutandis, to the scholars in whom Parry abodes so much faith. But although they interact with ancient texts, they have little occasion to interact with the kind of world in which the texts were produced. They are out of touch with that experience. The fact that Parry takes comfort in the analysis of Peter Enns doesn't inspired confidence.
iii) The extent that "the majority of OT scholars" agree with his interpretation overlooks the fact that the scholars in question don't believe the OT is true. Indeed, most of them don't believe the OT could be true. Because they are emancipated from concerns about the authority of Scripture, they feel free to indulge in interpretations which, in their opinion, contradict known facts about the world. They don't feel responsible for upholding the veracity of Scripture. Indeed, they presume that Scripture is often wrong. They operate with a secular outlook.
As, however, an "evangelical universalist" (cough, cough), Parry needs the authority of Scripture to leverage his optimistic eschatology.