In reply to CharlieMack:
Definitely check out accommodation availability as a LOT of places shut at the end of august (as we found in the first week of September in the Rondane). The Otta campsite at Selversket was shut but you could call a number and get the keycode for one of the self-catering huts and leave money in an envelope when you leave . I think you can send off to the DNT for a key for the unguardianed huts & winter rooms.
Anyhow, we did 8 days in the Rondane which was great. All huts bar the Rondvassbu hut were virtually empty. Mountains were a nice mix of UK-type mountains, hardly any people, and euro-type marked paths - you could go off-path like you would in the UK in a lot of places, yet had signposts and good marked paths like in the alps. we stuck to the paths
Temps were good for walking, but we had ice on the inside of the fly one morning, heavy rain on one day, and rime on the high summit cairns e.g. Rondeslottet, so you do need to be prepared for that. Happy to share our route if you want inspiration.
One Norwegian chap we got chatting to said the Breiheimen area was the best for walking in the country so you may want to consider that. We also took the scenic train from Otta to Andalsnes under the Troll wall, a good option for an easy 'end of trip' day (Otta's a lot lower altitude than the Rondane itself so you don't want to be going up and down).
Rondane 'vegetation line' was at ~1400m with bare rock above. bare rock was essentially giant piles of bouldermat-sized slate chunks on the mountains themselves, so quite 'steppy'.
Post edited at 13:13