I've had the best luck with beaver carcasses and horse meat for bait. Powder river paste bait will work as well but not as good as the other two. Bobcats rely more on sight than smell. Always hang some sort of visual attractor near the set to get them close, as was suggested, feathers, or tin foil, glass christmas balls also work well. Trapping the rocks you will probably be better off using a drag, never good to have to put the trap where you can get a stake rather than putting it where you want it.