How do you plan when you don't know the books?

I have very excitedly expanded what books we’re going to read for our upcoming study of Early American History. I had thought I’d do Module 5, then added Beautiful Feet, and now have also added other recommended books and some from TruthQuest. I have only worked though the arrival of the Pilgrims but I’m so excited to have heard of so many wonderful books for this time period. I want to read them all! Last night I culled the list and I’m going to go through them all once again to pull out a few more that seem like they may not be quiet as wonderful as the rest. The question I have is how to plan for such a schedule. I’ve never scheduled history before and my sons are starting 2nd grade. I think I’d like to have a goal of me reading aloud from this list for 30 minutes 4 times a week…so 2 hours a week (plus a few of the books which will work well as our bedtime story). It doesn’t really matter to me at this point how long we spend covering the material – one to two years seems fine as long as we’re all still enjoying it. I’d like to have an idea of which we’ll be able to read during just Term 1 at this point. But I don’t see any way to do this. I don’t have the books in hand. Most will be acquired through interlibrary loan hopefully so I don’t really know how long each will take. Are there any tips of how to plan for this type of scheduling style? Do I just keep the list of what subject comes next and take each as it comes, never really knowing how long each will take? I can’t seem to come up with a system that is more ‘planned’ but thought maybe someone here has some tips for me.

Thanks!!