Hi,

He lost his fear of fear; he ceased to think about his accustomed life of two aisles and the show-case of new models and the background of boxes and boxes and boxes of shoes--tokens of the drudgery that was ground into him like grit. The Father who worried was changing into the adventurous wanderer that henceforward he would be--for two weeks.
(The Innocents by Sinclair Lewis)

What does " his accustomed life of two aisles" mean?
And what does "tokens of the drudgery that was ground into him like grit" mean?

Thanks