Alaska: Summer camping or September hotel ?

Hi,

I am planning a trip to Alaska in 2007. I have seen several great
tours which involve either summer camping (July and August) or are
hotel-based (first 2 weeks of September). Which would be the best ? I
would like to avoid the mosquitoes and tourists as much as possible,
and hopefully see the Northern Lights, whilst having a decent weather.
I am looking for anyone who has experience camping in Alaska in the
summer: is it cold at night and is there a lot of rain? Does anyone
know what is the weather like early September ? Any response would
help me make my decision, since it is a big trip (I am based in
Belgium, Europe) and would like to make the right decision.

Thanks !

Marianne