Sorina, you have started a thread that I think will be bombarded by replies. For me, well, it depends upon ones motivation. To walk alone means that one has hours and hours, days and days, of silent introspection, for contact one has to reach outwards, to new people and new situations - to me, that walking alone is an absolute necessity if making pilgrimage.
If, however, it is a long walk then go with a friend - with a friend what would have been silent hours and days - passing through fear and loneliness to peace and courage - will be filled with talk about home, what Steve or Sue did at the last picnic, what work is like, what colour to paint the sitting room .... instead of internalising the pain of tired legs one will tell the other person - introspection is gone, personal progress is gone.
Your choice - it is all pilgrimage.
Buen Camino