LOL, yeah that is quite a few tourists you have there. That can't really be causing the virutal memory, no drive space related issues if they never appear on screen (imagine if they all came over to visit you at the same time!) but it's not really expected either. Do you not have NRaas Register in play? Tourism is controlled by that mod and you can set a more reasonable cap on them, like maybe 10 or 15 or the level you really want. Or 0 even (meaning set Allow Tourists to False) to get rid of them all hopefully within a sim day or two and then set a more reasonable level.
A Resident population of 126 for most worlds is just fine. Some of mine go well into the 200s, not that I would recommend that for everyone.
On the full C drive, well that would explain how this happened. And at high graphics options, your game is going to try to reach for more virtual memory at times, but that's a function of Windows and it's going to try to use more C drive space for it than you could possibly have to work with while the game is running and has an extra copy of itself inserted into the Current Game folder, again all taking place on C.
I would suggest moving your user game folder out of Documents to your Desktop or some other location temporarily so it doesn't get messed up in the process and then redirecting your entire Documents library to the D drive. This shouldn't be difficult to do, but I don't have a Win 10 install near me so I can't give you screenshots of my own. This is the first hit I got on Google, though.
http://www.dummies.com/computers/operating-systems/windows-10/how-to-change-the-location-of-user-folders-in-windows-10
Maybe other here can tell you how they've done it, in case that doesn't work as expected.
From a Windows expert on MTS:
http://www.modthesims.info/showthread.php?p=5276232#post5276232
(look for post # 35, not the earlier ones where some of us were "arguing" about other things ;) )
