A large DP is not the best choice for everyone. If you bought that 2006 DP coach 4 years ago, the amount of depreciation alone would probably have paid for a smaller gas coach, which would have also served your needs. Now, you are concerned about the value of your large coach and whether you will be able to get out from under it before something major happens that will cost you even more.
You employment situation means that you cannot use it more and that the large DP was not the best choice for your travel needs.
I hope things work out for you without too much impact to your wallet.