How to get to hostel from Luton airport, we arrive in Friday.
I agree with andrejcheck. National Express is around £11 and both the Jubilee and Metropolitan lines go to Wilsden Green. Keep checking your email since a few days before you arrive, the hostel will send you foolproof directions from the Tube station to the hostel.
You can take the National Express bus to Finchley Road, and then the subway westbound to Willesden Green. There you are only 500 meters from the hostel.
You can check Google Maps, it works really well for London transport!!
Get an answer from Palmers Lodge Hillspring staff and past guests.