I'm going on my gap year trip to central and south of Peru soon and with Christmas just around the corner, I need to decide what camera to take with me. I'll be taking plenty of photographs but I'm torn on an issue.

I currently own a Nikon D3100 and it has served me well but it's a fairly big thing, especially with my 80-300mm lense. Most of my travels will likely be by bus but I will still be hiking, especially up in the more mountainous areas. Will carrying it cause me issues? Will I find it annoying? Is it too great a risk of being stolen, or paint me as a target for pickpockets etc? To what extent will a side-on camera case help?

Otherwise I will get a more compact camera, which will be lighter but limit my photography in other ways.

EDIT: I should have mentioned that photography is a hobby of mine so I will be taking extensive pictures of everything. Indeed, the month of my two-month trip is a wildlife photography 'internship' in the Peruvian rainforest (although the people I'm using are providing kit for that - the travelling afterwards is what I'm worried about).