You won't be able to pick your date, but if you are flexable and can pull up and head out at a moments notice, I believe you can get on the reservation sites and check for openings weekly I think you can get in.
for future trips if you have a date in mind, I always get it reserved early morning on the first day it becomes reservable, that way you get your date.
some parks are full for the year in the first month of the year, but there is always a plan "B", i MYSELF LIKE PLAN "A"
for instance we like to hike up to Mount LeConte Lodge in the Smokies every couple years, when we get the date figgured out I have 4 people on the phone on the exact second it opens, sometimes it takes a couple of hours of all 4 of us calling to get through, but so far we have always got out date.
