should the harddrive have a partition for the page files/cache to help with speed?
Partitions do not help speed. On the contrary, it reduces speed but increases wear and tear. Compare it to a large loft you have to store your stuff. You can easily walk around your loft and get the stuff you need. That is comparable to a non-partitioned disk. Now imagine that same loft, but partioned into two or more parts with a wall and a door to separate the parts. You have stuff stacked against the wall you need, so you get it, but instead of getting the other stuff you need just 1 foot behind it, you have to walk 12 feet over to the door, open it, walk 12 feet to the other stuff you need, return 12 feet to the door, close it and then go about your thing. You have just walked 36 feet, where without those partitions 1 foot would have sufficed. Not very efficient, right? Same with partitioning your disk.
The basic thought on where to put what, is to distribute disk accesses across as many disks as you have. If you have a workflow where you export only a few times, or once when finished, then put your projects and exports together. Remember that SATA is half duplex, so you can only read at one time and write at another time. You can't do both at the same time. When exporting the project is already loaded, the media need to be read and written to the export disk.
Here's what I'd do.
SSD: Windows and Programs. (Leave paging alone.)
2TB: Projects and Scratch (including Media Cache)
2TB: Exports/Encore Images