I tried going back to cage/straps on my rigid Marin MTB so I could ride with running shoes (for those casual rides). None of my running shoes fit or felt good in the cages so after a few rides I swapped the pedals for platforms. After riding a couple decades with SPDs and cycling shoes I couldn't get used to the non-stiff soles of running shoes and the feeling of not being "clipped in".

I've since gone back to SPD's and cycling shoes (on all my bikes)....except for my Beach Cruiser.

Re: Clothing....I wear either cotton or Dry fit T's with cargo shorts with padded cycling lycra underneath.