你好！Justin， Yes，that's interesting!这3个词的意思【慢走】使用的频率最高，最常见。好走，次之；走好，用的最少。 These 3 words【慢走】is most frequently used and 【好走】takes the second,【走好】is rarely used. 【慢走】有2个意思： 一个是：don't go yet，就是别走的意思。比如：慢走，我还有个事情没说呢！ 另一个是:good bye,当别人离开你这个地方时，会说慢走，因为我们觉得走慢一点安全，所以慢走就是希望你安全到家。 欢迎下次光临，您慢走！ 【好走】：也有2个意思： 第一个是：good bye.也是祝你一路路好走，顺利到家，强调路上不会遇到障碍。比如：好走啊，不送了！ 第二个是：convenient for walking 。比如说：这里的路没有你们城里的路好走，城里的路又宽又平坦，农村的路你得走慢一点儿。 【走好】：这个词有点特殊，这个经常用来表达送别已经去世的人，希望他在去另一个世界的路上without a hitch . 比如：您也没来的及看我一眼就走了，您一路走好，孙子会想您的。 所以“走好"一定要慎用。但是不排除有些地方的方言会用”走好“说good bye. 希望对你有所帮助，欢迎大家讨论补充~ Comments and criticisms from readers are welcome.

“好走” exists in some Chinese dialects for example in my hometown in southern China we do say "好走" as well as "慢走". "一路走好" is also a word for saying goodbye but it sounds less casual. I am not sure if you can use "走好" independently. It might be the way how they say it in some northern Chinese dialects but it needs to be confirmed. In standard Mandarin, you should perhaps only say "慢走" or "一路走好".

actually they are both oral Chinese . they have little difference.