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I've never done myself as the vent hole on my Surly with dynamo lights is tiny and I can't get the cables through. I just zip tied to trailing edge of fork.
For internal I think it would be into bottom of fork leg. Out the bottom or side of the crown. Then light from front light to rear would feed into main frame a la di2 type grommet. Then out where you want it in the rear.
So for you future proofing. I'd say access grommets for the cabling and thought into fork design to allow easy routing. However if you're going carbon fork I'm not sure. Perhaps wind-up can be made w access ports?
Might be worthwhile considering having the frame made with internal routing options so you can run dynamo lights when a future need arise?