You'll have a great time. Where you are going hiking is nothing short of breathtaking. And if it's cloudy when you get there, have patience and hang out a bit, as it may just clear up with the sun shining, as did happen when we were there.
Definitely take the road to State Line easy. If you can, travel with your toilet empty.
If that involves emptying to a blue tote or using the latrine there, that's what I would do.
Dave