#7. "RE: D5100 as an unobtrusive travel camera?" In response to In response to 5
I picked up a D5100 recently having tried and quickly returned the D3200! The idea was the same as yours: for travel and being unobtrusive.
The D5100 is one of Nikon's best kept secrets and surprisingly, so is the 18-55 kit lens (which I almost didn't get, because of the 'big guns' I already have (24-70 & 70-200 VR). This neat little camera is compact, produces amazing resolution with a magnificent LCD and if you shoot video (I currently don't!)you will love the ability of the LCD to pop out -- allowing you to get great angles. You can get those great angles on stills too.
I have even been enjoying the 'effects' mode possibilities for the fun images you can get. Its important to know its limitations regarding lens options, but that is minor compared to the quality of images you can get with this gem.