The hard plastic hose is cheaper than the rubber hose which is why car makers use it, there is no "better" between plastic or rubber hose in this application, just a matter of cost.
There should be a Black line to check valve and Gray line to heat control.
You should be able to see them between inner fender and Blower/evaporator housing
You can get correct diameter rubber hose that fits snugly over the hard plastic line to do repairs, or to replace whole lengths and route it as you see fit.
No clamps are needed since this is a vacuum system, it tends to pull the connections together vs push them apart like a heater hose connection for example.
But up to you, simple zapstrap/wire tie will be fine
Usually you can cut the hard line and leave a few inches sticking out at the firewall and replace the middle part to check valve, and/or Heat control valve, with rubber hose
Wrecking yard will be the only place that will have the whole lengths of the hard plastic lines, and they are often damaged so check carefully.
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