Sorry to hear about your problems. However, don't give up the ship just yet
I have been a member on another forum because of my previously owned RV and there are many more complaints of cracked holding tanks there than what I have heard on the Jayco forum. I saw a video on how these tanks are made (not at Jayco) and am amazed that there are not more tank leaks. It seems to be a rather antiquated manufacturing process to me. Thanks goodness for the two year warranty. I have had the propane problem as well and it stems back to opening the tank valve too quickly. When it happens to me, I shut off the valve, disconnect the hose and let it sit for 30 minutes then reconnect the hose. Make sure the connection is tight and v e r y s l o w l y turn on the gas. As for the caulking issue, I have also heard this one on several forums and it seems no rv manufacturer covers this so I make it a yearly maintenance item.
Good luck and I hope it works out for you. We are extremely pleased with our Jayco and the responses we have had from Jayco themselves. The only other advise I could give would be to find another Jayco servicing dealer other than Camping World. Some of their outlets don't know...well maybe I should just say, you can do better