Here are the routes on Thor I have done:

The one from Lower Boy Scout Lake that hikehigh mentions is gray; we call it the Secret Route. (It's hard to see on the map above; it's just to the right of the yellow one). I agree that it is the technically easiest route on Thor. But it has about 800' of loose scree to negotiate. The east couloir (blue) is similar; it is a little less loose, but much longer.
But I also agree with tomcat_rc that Smiley Face (dark red) is overall easier. It starts higher and doesn't have any looseness. It does have two very short and easy sections where you have to put your hands on rock--but not enough to elevate it beyond class 2.
Similar is the southeast face route that hightinerary suggests (orange, southern start). One short section where you put your hands on rock. And from Mirror Lake (light purple) there is also a rock section, but it is more serious class 3 and longer than the others: about 30'.
I think what Richard P. has in mind is for you to peruse my sets on Flickr, looking for those that have Thor in the title. Poke inside to see which route--several of each to look at.
Is this more than you wanted to know?