A DD 2 stroke with a complete exhaust and intake system is the least of your worries in a stored coach that isn't driveable. Water in the fuel, remedied by keeping the fuel tank full, and the air system will be your more likely source of problems.
If the coach is stored indoors, it could sit for years and start right up...even with 2 year old fuel.
As Dallas stated, there are ways to "store" the engine.
If your fuel tank is full of crud, it'll be more full when you start it....if it sits for years. Tanks could be cleaned...and fuel filters will have to be changed a little more frequently.
Brakes locking up, air system valves, wheel seals on oil hubs, automatic transmissions, clutches, and coolant leaks may also cause problems. And, if rainwater settles on the engine, you very likely will have water in the oil....eventually.
If the engine is pretty worn, you may wish to pull the oil pan drain plug if it sits for a long time and verify that no water is in the pan. It'll settle out on the bottom of the oil pan.
A worn 2 stroke may seep a little antifreeze into the engine. This could be considered a dying engine.
Now lets get that sucker driveable...! How long can it take?