Yeah, 2001's are notorious for rot. If it has one soft spot, you may be in for a secondary or even full stringer replacement project... BEWARE.
On CCFan somebody mentioned a moisture meter. (8122pbrainard's second post and down)
Although he may not let you use it, I'm pretty sure it involves drilling. An easy way is to check the engine bolts. If they don't tighten down, chances are its rotten. If you do buy it, you won't be disappointed with the wake. Dang I type too much.