I bought a D3200 for similar reasons and couldn't be happier. I've never tried the D5100, but it's supposed to be an excellent camera with a tad more high ISO capabilities and auto-bracketing. The nice thing about the D3200 is that with the 24 mp sensor I can crop so tight that I can leave my long lenses at home. I bought the Nikkor 10-24 & 24-120 f/4 which will be the only two lenses that I am going to take on my trip. They are both stellar lenses and relatively light weight. Bring an SD card with you and take a few shots at BB. Even the kit lens, the 18-55, is remarkable for the price. And, if you buy the 55-300 with either camera, you get $150 off. It's not a 70-200, but it's a pretty good lens for the price. The 55-300 might be better on the D5100 since the sensor resolution is lower. Take a look at DxOMark's sensor tests.