The part of the trail most damaged by the fires is north of I-10, so you’ll probably be OK in that regard. Down in San Diego county, a few sections of the trail were overrun by fire. There’s the possibility that some of the trail might still be included in forest closures for post-fire rehabilitation in January, even though the trail itself didn’t burn in the closed area.
I’ve been on top of San Jacinto in winter, via the arial tramway. It often gets fairly snowy up there (it’s a cross-country ski area, after all), and it can get cold in a hurry. Please (re)read some of this year’s PCT journal entries – some hikers were seriously affected by weather along the route in April and May. Frostbite and hypothermia are very real problems to consider. So is losing the trail. Take topos and a GPS, and make sure you know how to use them! Carry a radio and a cell phone. Consider renting a satellite phone.
I’d be concerned about the length of your proposed hike. Keep track of the weather by phone – 200 miles is a long ways to hike, and the weather could get really foul between your planned town stops. Study the maps and trail guides, and mark all of your possible bailout points. Do not commit yourself to the entire 200 mile hike: be mentally prepared to bail at any time if the weather changes. Don’t be resistent to turning around and going back, if that’s the fastest bailout. Stick to the trail, though: unless you’re familiar with the area, a cross-country “shortcut” or bailout in winter is very risky.
Take extra food and fuel: you might be stuck in the woods for an unplanned 2-3 days if bad weather comes in. Take a winter sleeping bag. Take two inflatable matresses. Take a tent. Take extra socks. These are not Ray-way conditions.
File a hike plan with a responsible person, then check in on schedule. You can’t be rescued if no one knows you’re lost.
Craig “Computer” Rogers