On my last Challenge I sent a parcel to the garage which, if things are still the same, is also the post office.
In previous years we have camped down by the public toilets and also at the south end of the village near the old bridge, this puts you in a good place to use the track up to the quarry rather than the usual route via the aqueduct track.

No public toilets in Dalwhinnie now, the building is used for something else, but the spaces nearby may still be OK for camping.

Thanks Kirsten hope to see you next year as I’ve just seen my “Good news” email!!