Ok, I fixed this.
The "Drives" application in Mint 17.2 was, for some reason not correctly editing my fstab file. I'm not sure why. So I set out to edit fstab manually.
It may look imposing but is really not. This Ubuntu help document explains fstab fairly well. Between reading it and looking at the part of my fstab file that did work it took me maybe 5-10 minutes to fix this issue.
First, I booted into a live session off of USB, then:
mount / filesystem (a separate partition for me with how I have Mint 17.2 installed)
cd to /etc directory of now mounted /
sudo nano fstab
delete incorrect entry at bottom of fstab file (applied by "Disks")
ctrl + x to save
mark out first line with # to briefly desribe the partition I want mounted at startup (not required, I just did so for my reference).
next line starts with UUID=
to find UUID of all drives open new tab in terminal (or separate terminal)
sudo blkid
find UUID of drive you're wanting to have automount, copy it to clipboard
back to other terminal with fstab file, copy UUID string to fstab directly after UUID=
a couple of spaces over to set mount point (usually /media/whatever you want it mounted asDO NOT USE ANY SPACES!)
tab or space over a bit more for filesystem type (ext4 in this case)
for options the defaults were fine in my case.
for dump I set it to 0 like everything else in my fstab.
for pass I set it to 2 (0 would have been ok I guess, 1 is only for root)
look everything over to make sure it's ok
ctrl + x to save
sudo mount -a
Then I rebooted back into the system. Worked like a charm on the second attempt. The first attempt I just forgot to set the mount point. Not too difficult.