AND he picked up your cardboard and recycled it for you! That's sweet and manly all at the same time!
Anyway, I know what you mean about being "cozy in your solitude"...and then all it takes is one connection with the opposite sex to realize at least spending time with "one of them"

for a bit might be nice. (I have been in that exact same spot.)
You could perhaps just start by walking his little dog with him one day. (I love guys with dogs, but then I want one so badly right now but can't for several reasons.) Obviously he cares enough about animals to have his own, but then he ALSO cares enough to take the dog on proper walks, which a lot of people don't do.
So I think it's nice you have been talking with him, and I am glad you feel positive about it. Just take it slowly, and even if he only turns out to be just a friend, it sounds like he might be a very kind and compassionate friend to have.
Hugs to you and do keep us updated!