Just use the stinky slinky between them, and then lift the middle up to get the last bit to run down into the tank when you’re finished. It will work just fine how you’re parked already.
Connect with a stink slinky cerefully.
cinder blocks have been known to shatter – I would say not to use them to hold up a camper by themselves.
See those little yellow pads your jacks are parked on….