I completed this upgrade and agree with the previous comments that there isn't much tubing to work with in the camper. Attempting to pull the old value out of the tubing was no happening, so I cut it off. I was then able to work out some tubing to seat the new flange. I was not able to seat the flange completely, but it was well seated, I used the hose clamp and did not have any leaking after it was attached. As I noted previously, I was not able to seat the new valve completely in the flange, but I wrapped some teflon tape around the exposed threads to keep it free of dirt.
Someone had commented that they would just change out the failed plastic value every few years. I cannot imagine having enough tubing to complete another replacement, and it would require either adding tubing or replacing the entire run of tubing.
Thanks for the upgrade tips!