Instead of four tracking part or the whole route to Micklefield a tunnel could be built (about 3.3 miles) from Neville Hill to this new line that is to be built as part of HS2!
(Four tracking to Neville Hill is aspired anyway!)
That should be able to take off all the fast services to York and beyond!
As for the fast services to Hull, put a chord in branching off this new alignment, around the top of Micklefield before rejoining the line at South Milford.
By building effectively a new route you wouldn't have to rebuild Garforth, East Garforth or Micklefield. East Garforth wouldn't have to close, (which it might to mitigate stopping at Thorpe Park) Garforth's original station building wouldn't have to be demolished. I don't have a personal opinion on it but I bet some of the locals might!
Once services are off the existing line, you could even put a chord in above Sherburn in Elmet to give that a decent rail connection to Leeds, then possibly extend some services to Castleford or as far as Wakefield or even Huddersfield once TRU is done!
The best thing about it is that you could then build another station at Killingbeck with ease, the alignment over Selby Road is wide enough although it might not be if it was four tracked. The entire line to Micklefield is ideal for a clock face service!