When I was in Chama about 10 days ago it sounded like 484 was headed into the shop shortly, and would be done "before the snow flies." 489 apparently needs over-winter work, so the idea was to get the '84 done this fall. How the adventures with 487 may have affected the schedule would be something somebody at the C&TS might comment upon.
As to the D&S shopping the 498 for the C&TS--I'm sure they would want a bunch of money, plus a K-36 (maybe 483?). I don't think the C&TS would be inclined to part with 483, and certainly right now the money is not available to purchase a rebuilt K-37. In speaking casually with some the D&S shop people, they indicate that the 493 (currently sitting in the elements at Silverton) would be a better candidate for rebuilding than the 498. Unfortunately, any K-37 has the pre-1912 boiler which complicates certification and inspection (at least that's my understanding--correct me if I'm wrong). All K-37's still suffer from some deficiencies from being converted from standard-gauge locomotives, namely being heavy on the firebox end which leads to trailing truck problems. If the C&TS wants another K-37, 492 might be worth rebuilding--at least the C&TS already owns it.
As to winter operations, I personally think it's a dicey proposition, financially and operationally. The D&S pretty much runs year-round, but I think their "non-summer" operations are pretty much a break-even proposition, even though they pick up traffic from visiting skiers. By operating only as far as Cascade, the D&S's exposure to winter weather risk is relatively low, except in the most severe storms. The C&TS's weather risk is much greater. The Cumbres Pass area has a long record of capricious, unpredictable, and vicious winter storms. Nor is that risk limited to the highest areas. Anything above Cresco on the west and Lava at the east is at risk of severe winter weather and blizzard conditions. One of the reasons the D&RGW ceased winter operations over Cumbres after 1966 was that they no longer had the excess equipment, manpower, and infrastructure to mount snow-fighting and "rescue" missions if a train got stranded "on the Hill." A passenger train stranded between, say, Big Horn and Los Pinos in an unpredicted winter storm could be ugly to contemplate. And could the C&TS attract enough passengers to make any type of winter operation pay?
One final note to non-Colorado and non-New Mexico readers. It has been several years now since this area has "enjoyed" a real "old-time" tomcat of a winter. So the last few winters have hardly been indicative of what CAN happen in narrow-gauge country--weatherwise anyway.
My $ 0.02