I've drawn the toolpaths in V Carve, I was thinking there would probably be a better system or software for machining the part though. I wanted to machine a number of these from a length of bar, drill the various holes, saw them to length and then flip them over into a fixture, machine the rear of the port block and machine the steam paths on the block.

In V Carve I've defined the areas to be surfaced, added pockets, I was planning to machine the part using a 6mm diameter endmill, just using 2.5D machining.