I haven't done Sunset in the winter, but it is otherwise a fairly straightforward hike; the top half is all exposed above treeline so could be nasty in the wind. I would bet there would be ice up there. It gets a lot of traffic and is a beautiful hike. The road up should be about 20 minutes one way. Lots of skiers will be there doing various backcountry ski trails, including Teardrop.
Maple ridge coming off the forehead is very steep, scary steep in a few places with some exposure. I have snow shoed up to that ridge several times but have never gone all the way up the ridge in the winter either. It is very rugged, and I haven't seen any sign of anyone else's tracks on the ridge line, so I get lost and lose the trail. I am also not sure how many people ever go off the back side of maple ridge down to the CCC road in the winter either, so that could be hard to follow too. Maple ridge is very beautiful though.
So it would be a great loop in the spring/summer/fall, but I wouldn't necessarily try it as your first winter hike on Mansfield. Coming down via halfway house or laura cowles would be much, much easier.