First of all you should use CCleaner every month or so to flush your system of cookies, temp files, etc. You will want to close all of your browsers before running the scan.
You can edit windows to use a hdd directory for your personal files if you have that many personal files. Most people dont have enough documents, pictures, music to require this.
You can go into your default browser and change the location of your download folder to be on your HDD. Every browser is different for this process but a quick google search should get you a good tutorial for your broswer of choice. Now if your download folder gets this full you should be clearing it out from time to time anyway and archiving the program install files you dont want to some place else.
As far as game capture and any other prorams, each one has their own settings that you should be able to tweak to use a different directory then default.
Also if you want programs to be installed to a different drive (like games) you can specify that durring the install.
There is no change one setting and everything will default to your HDD unfortunatly. Since windows is on the SSD as it should, it will be the C drive, and your programs are coded by default to use the C drive as they code it for what the majoridy need and the majoridy only have 1 drive. You cant change your default drive wihtout it effecting windows and screwing everything up.