Scott-- Yup, if you want a wide 285 series in a low profile and all-weather tread tire, then the Maxxis - Marauder in 285/55R18 is your only available choice (all of the others in this size are summer/rain tires). I understand your winter snow concerns, as the State of MA probably has some challenging winter weather.
I also have a very strong suspicion that you really like your new 9" wide wheels, and you would prefer to utilize them. Perhaps another tire option with much better snow capabilites is the GENERAL - GRABBER AT2 in P255/60R18 (30" O.D./39 lbs). This tire just barely missed being Snowflake/Mountain rated due to its 255 series width; however, it still has a super-deep tread depth of 17/32nds and will flat destroy any snow in its path!!! When shopping for tires, also look at the "tread depth" specification (the Marauder is 11/32nds tread depth). The AT2 is the exact same series width (255) as your current Nitto T.G.'s, and just a tad taller (60 aspect ratio) with 30" O.D. (exactly the same as the Maxxis Marauder). If you can live with a 255 series (instead of 285), then the Grabber AT2 in P255/60R18 might be a better snow option tire for you. Check out the Grabber AT2 at www.TireRack.com.
In addition to the Grabber AT2, there are many more "snow" options from various tire manufacturers in the size of 255/60R18 (30" O.D.). Further; Pirelli Tire for example does make a wide 285/55R18 in their Snow & Ice tire that is Snowflake/Mountain rated. The major problem with purely dedicated "snow tires" is their rubber compound is fairly soft in order to be grippy in the snow, and they will quickly wear out if driven on dry pavement. Thus, always check the "tread wear" rating when comparing tires before making your final choice. Hope this helps.