I take a 4-day motorcycle trip (800-1000 miles) every year on a Yamaha 650 twin, which is definitely not the smoothest bike around. I usually brink a Pentax K1000 and something else. For the Pentax, I just use an ever-ready case and wrap it up in clothes or towels, in either a tank bag or saddle bag. That camera has probably done at least 10-12 trips like this, and I've never had an issue. It even survived a small spill at 25-30 mph one year.
Last year, my second camera was an Ansco Speedex folder, which made the trip fine, but soon after I got back, I discovered that I could no longer select the slower speeds on the dial. I took it apart and all it turned out to be was the screws holding the inside front plate had backed out 1mm or so, most definitely due to vibration from the trip.