You can easy change MOD folder location.
1: Download and Install:
http://schinagl.priv.at/nt/hardlinkshel ... llext.html
2: Go to your ETS2 settings folder: X:\Users\XXXXX\Documents\Euro Truck Simulator 2

3: Right click on MOD folder and choose: Pick Link Source

4: Go to other location where you want hold your mod files. Example E: disk

5: Right click on empty space and choose: Drop As... -> Junction

6: After that new folder appears with similar name:

Open new folder, drop your favorite mods and play!