I ride alone half the time as well, I ALWAYS carry a cell phone, and an extra pair of warm gloves, and an extra heavier hat. I carry a long chain(with a lock), a tow rope, a full set of wrenches couple pairs of pliers, a spare belt, and a extra jug of oil, trail maps etc.. I make sure if its a long ride I know where the gas stations are, and there is no planned snow/wind storms rolling into the area. I also make sure I am wearing heavy clothing under neath, some people go out in tshirt and light pants, which is fine if you are in a group I guess, but if I have to walk 10+ km's, I know ill have a good base of cloths under the winter gear if I do have issues.
I figure if I do break down, I will tie the sled to a tree or metal gates that are off the trail if available, and call a cab for a ride(most likely a very expensive cab ride too), or hitch a ride. Then go home and get a trailer and vehicle. My sled is 12 years old now, and its not a huge loss if it were to get stolen if I do abondon it on a trail till I can go back. Till now, the only issue I have had was my secondary screwing up, and I was able to get home fine, just little bottom end,
I try not to go far at night if I'm riding alone, stay close to roads, and never venture out on the lake that I do not know.
its hard to find people to go out with all the time... and well, i have put the money into it, and i'm going to ride.
-steve
*keep it safe, always be prepared for the worst*