With great caution* I will tell you that the mission you describe is best accomplished with either a C 182 fixed gear with a STOL kit, or better, an older C 206, with a Roberston STOL kit. Such a C 206 would best be a "P 206" version, if you can find one, and with an IO-550 conversion. Such an aircraft will easily, and safely operate in 600 meters under normal conditions, and carry the load you suggest.
*That said, this is an expensive, and extra training required operation. Though very doable, this is specialized flying. It requires additional training, specifically on that aircraft type, and that operating environment. If your insurer does not demand it, your care for your family certainly should.
Consider very carefully the cost to operate such an aircraft, these are very expensive, compared to 172's. Many a new pilot aspires to such aircraft types, and operational capabilities, many fewer can actually manage the skill and finances to make it work.
I have lots of experience in Robertson STOL C 206, and very recently a Horton STOL P206. Light, either is able to be off the ground in about 100 meters, and back on in not much more, when flown with great precision. A STOL fied gear C 182 will do nearly as well (older, narrow body 182 is better yet). Which takes you to the 185. A very good choice, but again, lots of training and skill required.