299 for sure, stay off 36.
Only four grades on 299 none that bad, the west side of Oregon Mountain is probably the worst going up the road is good and mostly straight but steep, 6-7% but about half way up is a 20 mph unbanked turn and you will loose all your momentum. Not a big deal we pull the 24'TT over 5-6 times a year.
Coming down the east side of Buckhorn is slow and windy but they are in the process of fixing a lot of that now. (construction shut down for winter, probably no delays) That part is only about 6-7 miles now.
Shouldn't be any snow this storm is pretty warm, but watch the shady spots for ice. If there is ice they will have it cindered, they are pretty good on that. But it sure makes a mess on your rig.
Safe trip
Tinbender