Black tank vale replacement

[Idalogger52]

Well it’s our turn to have the old leaky Black tank vale. Looking under the coach there is a 1/2” propane line that runs from side to side, about 10” from the edge of the coroplast. The black tank and shower grey tanks are both under this area. My question is how do you get the coroplast down without taking all that propane piping out? Is it doable or does the piping have to be dismantled??
TIA