It was hardware. Memory. I've been loading data since I originally posted. No exceptions so far. I had some issues with OOMs when I first started playing with cassandra. I increased the amount RAM to the VM and reduced the memtable size. I'm guessing it's because I'm using I3s. More cores would most likely improve GC performance.
I put all the logs and my configs on my google drive. The link is in the original post. I'm running 1.2.4. There have been two releases since my original download. I'm going to attempt an upgrade soon.
I'm also considering using leveled compaction. I just have two 750GB drives per node. I'd like to use more than 50% of the drives if I can.