I'd be all over that car if $2K or less and clean overall. Though a timing chain repair could be fairly expensive ($1,000+) though at least it would be done...along with belt, idler, idler tensioner, water pump, and probably vcg's and plugs/coils if needed. If you can do all the work yourself, not such a big deal. And the lady and/or her mechanic could be mistaken and not be a timing chain issue. This is pretty early for one of those to go...unless she's a lead foot driver (not likely). Just using the wrong oil filter can give startup ticking than sound like timing chain "problems."
The 1998 TC was specced for 5w-30. Then back specced by Ford for 5w-20 in 2001. Using that oil for the past 16 yrs could possibly contribute to more timing chain/chain guide wear...especially if OCI's were on the long side. My 1997 Lincoln 4.6 liter went 232K miles on the original timing chain, guide, and tensioner...all the way on 5w-30 conventional oil with 3K OCI's. That was a superb running 4.6l until the water pump failed.