The Hilton Garden Inn Hatton Cross (formerly Jury's Inn) really is 5 minutes' walk from the Tube station. I've stayed there twice as it's easier to get the Tube than faff about on the buses, particularly late/early.

However, bear in mind that most of the hotels along the Heathrow northern perimeter road are within the free Heathrow travel area - you can board any regular bus (avoid the HotelHoppa!) and get to them for free. But you have to get to the Central Bus Station first, of course. Tube is easier.

And, if you're tubing it, then you can surely head into town? And find a decent hotel near one of the Picadilly line stops?