When kai was that small, cute and innocent i basically used to let him walk/play as much as he wanted. In the house he'd sleep when ever he wanted and played when ever he wanted. Slept 80% of the time.
As for how far walking id say i took him for 2 10 min walks every day till he was 15 weeks. You could tell when he didnt want any more (id then just pick him up and walk around just to get him used to all the smells and noises
Uploaded a pic just for the cuteness (him at 8 weeks)
I tend to make play dates with healthy friends dogs (in their or my own yards) until puppy shots are complete. After that I start taking slow walks across empty park fields with pup on a long (25 ft) line. This allows them to have gentle exercise as they take their time playing around you. It teaches them the basics of recall from a distance, you can practice long distance sits and or downs, all sorts of goodies. They think they are getting exercise, but they are really learning at the same time.
IMO it's best to follow the puppy's lead with walks, keep an eye on them and go at a pace and distance that is comfortable for them (with rest breaks if they want them). I generally avoid a lot of long walks with puppies as it is considered forced exercise (because you are in control of it, not the puppy) and that type is not so good for growing joints especially if it's on hard surfaces like sidewalks. For exercise personally I try to stick to playing, fetch, and other things like that where the puppy can stop and rest whenever they want and they are in control of how long and how strenuous the activity.
I like to take puppies out to different (safe) places as much as I can as long as they are enjoying themselves but as for actual walks I'd keep it brief.
Also as others mentioned be careful where you let her go if she's unvaccinated.