It's been almost 11 years since I flown that route but I've done it several times in both directions. From what I remember, there's not that many outs if you have a problem. Most of the route is pretty rocky. Make sure you have enough fuel to get to Sitka, or even Juneau if the weather goes down in Ketchikan (also called "Catch it if you can").
If you're flying the ILS in, make sure you don't go right of course at all. There's hills on that side. Going left of course too far won't end well either, but at least you have a bit of water between you and the hills on that side.
Oh yeah, if you're spending the night, you'll need to take a ferry to the hotel.
Otherwise, it's a nice scenic flight when the weather cooperates.