Has anybody replaced the RST suspension Fork on a Trek Navigator 200?

Specifically anything with the extra long neck?

I bought my bike used. I believe it is a 2003 Trek Navigator 200. It's the 21 inch frame. The shock is bad I need to replace the front fork. The trek dealer in town has not been able to find a part for me. It appears they used an extra long neck on this model so I need a 275 mm neck.

I like the bike but have not been able to find a part to repair it. Is there anyone else who has had this problem? Were you able to find a part anywhere?