The Dutchess Four Departure has lost comm instructions which read, "If
radio contact is not established/lost for more than two minutes after
departing, proceed on course and climb to 5000 feet. Ten minutes after
departure, climb to requested altitude/flight level".

Let's say my clearance is "Cleared to HPN via Dutchess Four, V157,
HAARP, direct. Maintain 3000, expect 4000 after 10". If I go lost
comm, do they expect me to climb to 5000, stay there for 10 minutes,
then descend back down to 4000? Or stop my climb at 4000? Or climb to
5000 and stay there (which would presumably leave me WAFDOF).

I'm inclined to think stopping my climb at 4000 makes the most sense,
but one could make arguments in support of any of the alternatives.

The OROCA is 4700. 5 miles to the west, the OROCA goes up to 6700. MEA
on V157 is 4000, MOCA is 2700.