I wouldn't light a unit that has been sitting for a year or more, or even THINK about it on a unit like yours that has not been ignited for years! Mine will be just a year when I hit the road in June, but I will be doing a total clean and adjust before I leave, as I do with all of the LP components. Throw in an air conditioner coil cleaning, water tank sanitizing and a few other chores and the 19CCD will be ready to hit the road.
Find a 'qualified' repair shop or mobile RV tech and have the unit cleaned and bench tested for proper operation.
You never know who or what may have taken up residence with-in.