I'm still of the school that drawings should be primarily function oriented (although mindful of manufacturing). The manufacturer (being an expert in manufacturing) is then free to choose how to meet the required dimensions.
That being said, in recognizing that multiple suppliers are often used for various operations (i.e. a casting vendor and a machining vendor), our parts are often broken into separate casting and machining drawings.
If I were doing it in that way, the casting drawing for a part like this would include datum targets on the round ends to simulate v-blocks (similar to Fig 4-12 of ASME Y14.8M). You'd need a second planar datum represented by three pins to tie it down in the other directions. Since castings are often irregularly shaped, we often define the surfaces with basic dimensions and profile of a surface. Most recently, we've started using a note applying a standard profile (referenced to the casting datums) to cast surfaces and referencing the supplier to the solid model (which they seem to be okay with). Key dimensions that require tighter tolerances are still defined on the face of drawing.
From there, we will transfer the casting datums to the machining datums. I would tend to take a similar approach to what I described above, positioning one hole with respect to the other hole, however you can no longer relate the outside features to the inside features because they're described on an entirely different drawing. Hence, the flat surfaces will need to be located relative to your planar casting datum and your first hole will have to be related both your machined planar datum and your v-block casting datum (with basic dimensions, of course). The second hole would then be related to the first hole (a new datum), the second machined planar datum, and your v-block casting datum.
If using a one-drawing approach (which implies a single vendor), I'd go with my previous post. If using two drawings, I'd do it like described above. At the end of the day, function comes first. Best to leave the manufacturing to the manufacturers as much as possible.