I did the century last year. The route was well-marked, the stops were not as lavishly stocked as some other centuries I did, but there was still plenty of food/choices.
It looks like they've changed all the routes somewhat this year -- the descriptions don't mention any of the roads (Redwood Gulch, Upper Zayante) that I remember as being the killer climbs from the last time around.
I'm sure they've substituted others that are just as challenging though.
The routes this year are a lot different from last year. I think it is nice for them to change the routes every couple of years. This year's 100K is a lot nicer than last year; I really hate the long slog up Hwy 9 (both sides) because of all the traffic. This year's 100K climbs Page Mill in the morning and West Alpine on the way back. Both roads have great views and minimal traffic, though they both have little shade and can get warm on a sunny day.