Hydraulic will probably be the best for stabilization, but they will cost a fortune to have installed. Depending on the unit, expect $3+K.
Old fashion hand crank are nice. I like to add a piece of wood under them to spread out the weight, especially on softer soils. I also re tighten them usually after a day or so.
Under the frame is best. I would consider about 6 in total. One set up front near the front axle. One set in front of the rear axles, and another set well behind the rear axle.
https://www.amazon.com/RVGUARD-Trail...%2C184&sr=8-13
Be safe!