WHat if you were able to scavenge a treadmill from a house or Gym and take it back to your base/solar powered deathmobile? You could Use it to train your stamina.
Or bring back a punching bag to train your melee and unarmed. you obviously couldn’t train a bladed/pierce weapon on it, but you might be able to train a bash weapon on it. i would imagine that just giving the heavy-bag like 100% bash resistance and -100% slash/pierce resistance might work?
My inspiration for this came from watching ‘I Legend’ and how Neville and his dog used a treadmill to be safer than running outside.
Are there other items that you could activate/use for an hour or so for a guaranteed skill or stamina boost?