Try looking at a company called Enviorseal. This company developed a product for the military. Its main use is for roads in places like Iraq, but basically its like a paint that you mix with water and then mix into dirt and gravel and compact. Once dried this stuff is harder than concrete. Its now used for alot of ADA walking paths for parks. I contacted the company and they gave me a sample and some specs. Stuff is awsome. I used at a alternate pad at my local course and it is much easier then anything to install. Simply graded out a 4x8 foot pad that was 2 inches of loose dirt. Mix in the solution 50% water 50% enviorseal. Mixed it into the dirt until it was mud and then compacted it with a shovel, let dry two days and bam hard as a rock and just as tacky as concrete. Cheap product and has little labor. I probaly could have got a better level pad if I used a compacter but if your on a rough course and you have to pack in tools a shovel works fine.
Contact the company let then know your interested and get a sample of the product so you can test it somewhere. Its also a certified product by the US Green Building Council so its enviorment friendly