Manbearcat
Legend
@Quickleaf I think you've got it pretty much nailed in your 1-3. And, of course, you can use it! I wrote it up specifically for your use in your DM game. Would be a bit odd for me to say no
Also, I went back through that Skill Challenge framework above and I noticed some mis-written text that I copy/pasted wrong from my sticky pad. I fixed this part here in Misc:
If you use that Skill Challenge, or something like it, I would recommend ablating and revoking resource recharge (from general or specific accrued failure) as a means to put pressure on the PCs and overtly convey the threat. You could forgo the "no extended rests" until the fail that Skill Challenge on the first go if that is your wish...but I would rather recommend that the second failure of the Challenge costs them Extended Rests while ultimate failure results in a re-do. Further, you may want to use the intermittent group Endurance Checks outside of the accrued success:failure of the Skill Challenge and just use it as a rider check (for any Skill Challenge checks) where pass/fail determines resource stabilization or loss (Healing Surges and/or negatives to Fort, etc).
I agree with @pemerton thoughts above. If you aren't using it as a means to pace/dictate progression through an area/level (and ALL of the pressure/adversity the PCs would face), then you'll want to use it for a specific, singular pressure/adversity that is intrinsic to the level/micro-region.

Perhaps the PCs have to pass an intermittent group Endurance check (aiding for bonus and low man rolls it). Failure equals an accrued failure in the Skill Challenge, loss of 2 healing surges, and no Extended Rests effects/resource recharge until the group is out of the area.
If you use that Skill Challenge, or something like it, I would recommend ablating and revoking resource recharge (from general or specific accrued failure) as a means to put pressure on the PCs and overtly convey the threat. You could forgo the "no extended rests" until the fail that Skill Challenge on the first go if that is your wish...but I would rather recommend that the second failure of the Challenge costs them Extended Rests while ultimate failure results in a re-do. Further, you may want to use the intermittent group Endurance Checks outside of the accrued success:failure of the Skill Challenge and just use it as a rider check (for any Skill Challenge checks) where pass/fail determines resource stabilization or loss (Healing Surges and/or negatives to Fort, etc).
I agree with @pemerton thoughts above. If you aren't using it as a means to pace/dictate progression through an area/level (and ALL of the pressure/adversity the PCs would face), then you'll want to use it for a specific, singular pressure/adversity that is intrinsic to the level/micro-region.