Get your puppy out and about now. There's no sense in waiting and early socialization is so important.
You can walk/run your pup as much as you want so long as you don't push him. Watch for signs of being tired, hot, or breathing hard, and then slow down. You can pick up the pace again once he appears rested.
Every dog is different so it all depends on your pup how far is enough. Some are happy with a walk around the block and others, like mine, can't get enough.
Elaine and the herd