I think a great staring point now is looking at which teams in this league can we pick on should they not get promoted. There's a lot of quality players there that will be keen to go to a higher up club so won't necessarily cost the world.
Of the teams currently in the playoffs I'd go for a provisional list of:
Fleetwood: Mclauglin, Bell, Ball, Cole
Bradford: Meredith, Marshall, Knight-Percival, Vincelot, Wyke
Scunthorpe: Morris, Wallace, Adelakun, Madden
Millwall: Webster, Gregory, Hutchinson, Onyedinma
On top of that there are various loan players we can go in for out of that list that would also improve the squad (Brannagan, Toney, Dempsey) and loads of players outside the top six who have played well and give their right bollock for a chance with us in the championship.