I'd try this: Turn off valves on both (or single) propane tank/cylinder. Wait five minutes. Very slowly open service valve. Light stove top and let run. Try to start water heater.
It sounds like you have a mish-mosh of hoses and connections. There shouldn't be a hose clamp in the mix. The best situation is to have solid metal pipe/tubing to all appliances. A hose between a removable cylinder and the rest of the gas lines is perfectly acceptable.
A change in elevation won't effect any gas line attachments. There is a regulator between the tank/cylinder and the rest of the gas plumbing.
It may be that you are opening the service valve too fast and the cylinder's OPD is closing delivery or the same with a safety type hose.