I don't know how critical it is that Windows itself is on the SSD if you don't care how long it takes to boot up, but if you use a Samsung SSD drive, the Data Migration software does an identical clone of your original drive, so you don't have to reinstall anything. It will just recognize the new SSD as the boot up drive if you have the same hardware otherwise.
Having My Documents on the SSD is critical though, since the Sims 3 cache files are loaded from there, and it will cut time down significantly. Like I said, my desktop to saved game is under 2 minutes and my saves are under 30 seconds.
The SSD was the single best computer upgrade I've ever made, and it makes a massive difference in gameplay for me. Now I can play casually even if I can only pop in for a few minutes at a time. I really recommend the Samsung 840 EVO drives as they have some of the fastest read/writes among SSDs and integrated SLC/TLC technology.
Out of curiosity, why are you concerned about putting the CC only not on the SSD? If you only plan to install Windows and the Sims 3 on the SSD, you should have enough space for the CC as well.
Also, to get a sense of how much you can expect your load times to improve, are you on a desktop or laptop? What CPU, graphics card, and RAM do you have?