Update in case anyone else has similar issues.
I went back to the raspi and was determined to find the source of the issue.
Problem: raspi boots correctly, node syncs with the block chain, and then between 1 and 10 minutes or so (timing varies), the node disconnects and is unreachable by browser. Each time this happened I had to power cycle the raspi to get it running again.
I ended up uninstalling all of the node apps except for the core ones. I had to reboot the raspi 3 times during this process as it would disconnect the node before I could get very far each time.
After I finished uninstalling all of the extra episodes apps, it stopped failing.
It's uptime is currently at over 38 days. One or more of the optional third party apps inside of MyNode was causing the issue. I don't know which one, but if you use MyNode and have this problem, start by uninstalling apps.