I took my Nikon D60 on a ~500 km tour last summer. I just put it in a lunchbox with two big sponges (1 1/2" thick approx.) and strapped that to my homemade rear rack. I wouldn't recommend doing it, but it worked fine. No damage to the camera. I think DSLRs are more durable than most think. When it rained a bit I put it in a plastic bag inside said lunch box. I was worried that condensation might form inside the bag but it didn't seem to be a problem.

I saved up for a decent amount of time to buy this camera used with a standard kit lens (student here), so even though it's used equipment, I can't just go and replace it. Nor can I go and buy a point and shoot just for touring.

Really, as long as you don't get in a big crash, and there's a bit of padding beneath the camera, it'll be fine. The problem for me was that with my setup I couldn't easily access my camera, so it resulted in me not using it as much as I wanted to.