If you open the launcher and go to to the options tab. Look where the 'Install folder...' is and go to that folder. Once you are in that folder go into Direwolf20, then minecraft and finally saves.
So basically it is FTB\Direworfl20\minecraft\saves
Or Install folder\Direwolf20\minecraft\saves
Alternatively you can open minecraft. Click the Options button and then click Texture Packs button. Now click Open texture pack folder. Go back, up, one folder and then go to saves.
Texture Pack folder is FTB\Direwolf20\minecraft\texturepacks