We used to start in the Soo or Searchmont, after doing it a few times, we realized we lost 2 days on that trail on a trip. It is 6-10 hours by trail, unless you are carrying the mail, and not stopping to rest, pics, etc.... It is less than 2.5 hours in the truck to Wawa from the Soo, on good dry rds. It became a no brainer for our group.    Also, with the Ontario Govt switching from, the MTO to a for profit company (Ledcor) maintaining the highways up there, It is wise to become a member on FB of the northern ontario traffic alert page, and put the 511 ontario ap/site on your phone, and watch the alerts, and cams like a hawk. They have been closing 17 and 11 down very regularly for issues they never did in the past. Sometimes 17 is closed for days at a time between Wawa and the Soo. This will go on until the weather patterns calms, and or the bigger bays freeze solid, to limit lake effect snows in the region. Ski  

Short cut will save just over half distance of following trail approx 60 percent less distance. Then if he gets moose horn to give him 5 gallons of gas he won't have to go extra 10 kms into town from lodge on same tank of fuel. So that's how he could save almost 30 Kms off trip. ACYA told me about this years ago and me and my dad used short cut serval times over years. It's usually as good as trail and owner of moose horn was in process of cutting a trail off into power line to avoid ploughed road at lodge end. Road was never bad when I used it. 

I'm confused, which is it "18ish kms off trip" or "it be just be30km shorter then going into town"

I give you some great advice I learned when I rode area in past. If you use Sheppard morse road,  it isn't ploughed in winter except last few km's near trail on moose horn lodge end. Locals run it all the time. So it be a safe packed trail to use. It shave approx  about 18 ish kms off trip. If you call owner at moose horn lodge and tell him you need some gas, he have  it for you. Also a great place to stay in area so I wouldn't be afraid to head up and stay there and tell them you need gas. closer then town and with short cut you should be able to make it with minimal gas. It be just be 30kms shorter then going into town I did it this way before and never stopped at half way for gas.  cheers. 

The ride from searchmont to Wawa is great and worth the effort if conditions allow. I have not done it when halfway haven was closed tho…if trail was groomed and I carried fuel I would try it. Dropping in Wawa is also great option, it’s really not that much further when on the road anyway.. I did the big northern loop from there a few years ago. Wawa motor in was very accommodating for parking. We did stay over and leave from there as well as staying over when back. Good luck with the trip.