Hiking/Trekking in Norway in July --- what not to miss

I'm planning on going over in late July to visit a friend and plan to do as much hiking as possible. What are day hikes or hut to hut hikes not to miss. At this point, mainly planning on Jotunheimen National Park, Geirangerfjord, Sognefjord. I've read some ideas from visitnorway.com but really wanted some advice from those that have trekked there before. Thanks