I started Volume I of Gerhard Von Rad's Old Testament Theology. What I'm getting out of it so far is the following:
1. We have these creedal statements that were recited at cults, as well as stories about the origins of certain sanctuaries (i.e., Jacob at Bethel, Abraham at Mamre). With the rise of the monarchy, these stories were forged into a narrative about the history of Israel. Von Rad uses the term "Hexateuch." I wonder if he means by this the books of Genesis-Joshua, or simply the Israelite creedal narrative that encompasses the patriarchs, the Exodus, Sinai, and the Conquest. As far as the Documentary Hypothesis goes, Von Rad appears to date J to the time of David, and P to Israel's post-exilic period. In this scenario, there wasn't even a full Hexateuch until Israel's post-exilic period. But Von Rad may contend that the Hexateuch was organized on the basis of Israel's creedal narrative, which was rather old.
On the issue of independent stories being forged into a narrative, many scholars have argued that several of the stories in the Pentateuch did not originally relate to Israel's election as a covenant people. They were just stories---about the adventures of Abraham, Isaac, Jacob, miracles, etc.---and they were put together and made into a story about Israel as a covenant nation. My impression of Von Rad, however, is that he thinks that the concept of election was already implicit in these independent stories, on account of the land promise in the patriarchal tales (page 7). Personally, I read the concept of Israel's election as the backdrop for the patriarchal stories, but I'm open to other points of view.
2. Where does Von Rad stand on the historicity of much of the biblical narrative? Like Rainer Albertz, he believes that there was an Exodus group that left slavery in Egypt. He associates this group with the Joseph tribes. They joined up with the Leah tribes---only I'm not sure if Von Rad, like Albertz, holds that the non-Exodus group consisted primarily of indigenous Canaanites. My hunch is that he does not think so, for he continually talks as if the Israelites were absorbing a foreign Canaanite culture---as if they were not Canaanites. And Von Rad believes in a sort of Israelite conquest---he says that Israel beat the Canaanites when they were especially weak.
Joshua 24 is Von Rad's main proof that a Joseph group came to the Leah group and imposed Yahwism on it. Joshua is a Josephite, and he compels the Israelites to make a covenant to follow the LORD alone. Von Rad wonders: Why would Joshua have needed to do this, if all of these Israelites had experienced the Sinai epiphany, and had already committed to YHWH?
But Von Rad also believes that later authors incorporated their ideology into the Moses story. P, for instance, was big in Israel's post-exilic period, when there was an elevation of office over charisma, and, sure enough, P in Numbers highlights Moses as a leader, not a prophet; when Moses lays hands on Joshua in Numbers 27, he's passing on the office of leadership, not charismatic authority. Von Rad also thinks that the story of Baal-Peor in Numbers reflects a problem that the nation of Israel periodically had with the Baal-Peor cult---not an event prior to the Conquest.
And yet, Von Rad thinks that the Sabbath, circumcision, and the Tabernacle were things that Israel had before her entrance into Canaan. Von Rad does not regard them as exilic or post-exilic inventions, as some have thought in attributing them to P.
3. An interesting point that I want to mention: Von Rad argues that the Jews were optimistic that their exile would end. Only the elite was taken into exile, the land of Israel still had people after the Babylonian invasion, and the Book of Jeremiah records correspondence between the two groups of Judahites. This interested me because I've read scholars who have said that P wrote in exile the laws that he wanted Israel to have after her restoration. I wondered how P would know that there would even be a restoration. Von Rad's answer would be that the Jews were expecting one.