I want to give some advice. Start the St. Olavsleden pilgrimage route at Granavollen at Hadeland, with the Sister Churches and the charming Maria Church. There is a very informative pilgrimage center. Take the train from Oslo to the village of Gran, from there is just a short walk up to Granavollen. This is the best starting point for the pilgrimage, instead of walking through the grim suburbs of Oslo.
From Granavollen walk to the Hoff Medieval Church, and from there be sure not to miss the sticks out to Balke Medieval Church, a really nice church, while the walk here leads through the most significant and oldest cultural landscapes of Norway, part of our selected cultural landscapes.
Then walk down to the pier of Kapp by Lake Mjøsa and take the steam wheeler Skibladner to the Domkirkeodden church ruins in the town of Hamar. If Skibladner doesn't leave from Kapp that day, take the bus to the Town of Gjøvik, as Skibladner leaves from there every day. Eventually you can take the bus to Hamar, in July the buses costs less than 1 EURO or 10 N.Kr., no matter how far you want to travel. So if you get tired of walking, remember that you in July always can take a bus to Nidaros for 10 N.Kr.
At Hamar you must not miss the guided tours for Domkirkeodden, there are several different guiding's, one for the ruins, one for the plants and herbs, and one for the larger area. All the guiding's start by the ruins.
To be continued after church.
From Hamar you continue to Lillehammer, where you should walk the renown walking street and visit the charming Garmo Stave Church at Maihaugen Folk Museum.
At the village of Otta you turn right up to the Rondane Mountains, as these mountains are like a cathedral of nature. They're not too wild, neither boring, just perfect for meditation and inner reflection. I recommend walking the four day hike of the classical route Trekanten, or the Triangel. You can sleep at the cabins of DNT, or the Norwegian Tourist Union. Here you get dinner and breakfast, and if you become a member, you get a good discount.
Too don't miss the Vesleulfossen Waterfalls in Rondane, the tallest waterfall between Oslo and Trondheim.
Ps! Personally I would take a bus from Lillehammer to Ringebu, and continue the pilgrimage from Ringebu Stave Church. In my opinion the area between Lillehammer and Ringebu is too touristy, and it's from Ringebu the real interesting history begins. The time saved I would rather spend in the Rondane Mountains.