For rough terrain as well as rough use nothing beats a skid-steer loader fitted with forks. It has the capability to push itself out if you should be stuck and it also has the nifty ability to switch from forks to bucket without leaving the cab. The only drawback I can see is that you don't have the lifting height range that a true forklift has. As far as lifting capacity goes these machines come in a wide range of sizes and capabilities.
