OS on SSD, Win 8 "libraries" on HDD, access optimisations/cache?

Question

I have Windows 8 with

• OS/Programs on my SSD,
• A lot of data on my HDD
• ... Available space for some data on my SSD (My SSD being 250GB, I can reasonably afford 100GB for data)

Now I would like to use the "library" system of Windows 7/8. My HDD is often asleep, and when I need to access data stored inside or write some data, it takes some time to boot, and will freeze my explorer for a good 3-4 secs (I will also hear the HDD head starting spinning, which makes some noise)

Because I don't access my HDD very often, I'm afraid it means a lot of wake up/fall asleep operations (and the freeze time is also boring).

Is there a way to implement some cache ? For example :

• A Read cache for some files I access often
• A write cache : If I want to add some data, write everything to a temp directory, and after some time (before power off/sleep mode, etc. write back to HDD)
• Assuming I'm the only user trying to access the HDD (not shared on the network)

Basically, what a CPU Direct-Mapped Cache would do, but for large chunks of data (we're talking about PDFs, .docx, eventually some images or slides, even some video files).

The Idea would be to make this system as transparent as possible. Ideally : Clicking on library > "my documents" would show a "ghost image" of the HDD, showing all the files, cached or not, and only boot the HDD when trying to access a file that is not cached. Whn adding a new file, it would add it to the cache, and write back only modified files to HDD, only after some point (see above)

Are there built-in programs, or downloadable softwares that woul let me do this ? Or do I need to write my own scripts, and eventually setup some scheduled tasks ?