Will 24s fit on a 2000 Lincoln Town Car?

No, 24-inch wheels will almost certainly not fit on a 2000 Lincoln Town Car. The Town Car's wheel wells are simply not designed for such large diameter wheels. You'd encounter significant rubbing issues with the fenders, suspension components, and possibly the body itself. Even if you could physically make them fit, it would severely impact handling and ride quality. The stock wheel size is much smaller.