NWAlpine

A square knot is not designed to be used with two different diameter ropes, whereas a sheet bend is. The sheet bend was originally used to attached a rope to the corner of a sail (make a bend in the sail, or sheet, and then bring the rope through and around it). I've never used either of these knots to rap off of, but the sheet bend would seem to make more sense if choosing between the two. Personally I use the EDK first, or a double fisherman's when attaching different diameter ropes.

There is a difference between FWD and 4WD, although FWD with snow tires on a plowed road comes close to 4WD. Either way, you do still need to know how to drive both and know their limitations. My understanding of Oregon law (probably similar to WA) is that when traction tires are required in a snow zone, 4WD/AWD cars only need M&S all-weather radials (the tires that probably came with the car). In other words, you don't need to change out your tires twice a year. But to answer your question, FWD with snow tires will almost always be sufficient. You generally always need to carry chains in any car, because the police can require you to have them with you in case conditions deteriorate or you find you need them.