Penalty kill forecheck and 4 on 4 philosophies
On a 4 on 4, the philosophy is simple: treat it like a power play when you have the puck, or when the puck is loose; treat it like a penalty kill when the other team has it.
I recommend using your standard penalty kill forecheck when playing a 4 on 4. See the section on the Modified “T” Forecheck for the full explanation.
Defensive Zone Coverage:
Again, I recommend using your standard penalty kill coverage when playing a 4 on 4. Pick whichever one suits your team’s strengths and weaknesses.
Run a modified version of your current power play set-up. A four-man overload is very doable (think about getting the weak-side defenseman to slide down into the slot from time to time). A four-man umbrella is also very doable.