Way back on another website I summarized a few very basic principles to keep in mind when analyzing biblical texts — specifically for Old Testament texts but the principles apply to historical analysis of any texts — gospels included.
Till I get to finishing off chapter 5 this might be an appropriate place to stick a link to these basics (The Bible: History or Story?) because they are also a clear flag to show where I am coming from in my reading of the gospels and biblical studies. They all apply to B’s assumptions (not only his of course) except that the 4th listed in B’s case should be nuanced from “many generations” to “a single generation”.
They are far from comprehensive, they are basic “common” sense, they do not presuppose which way to read texts, and they help guard against bringing unconscious presumptions into the texts we read. We need to find evidence (not more assumptions or hypotheses) before deciding which way to read texts.
The link above is from my In Search of Ancient Israel.