Usually, you don't mine from the wallet with KMD, if you did, it is essentially the same. You can really just backup your wallet.dat, but the only issue is that there are ways to grow the keypool so that it needs another backup at a later time. You can do it as WIF, but then you may have a lot of keys to backup unless you mine using the "-pubkey" option. The discord has information on all these options in the #faq-chosen channel. People are also quite helpful in the #community-support channel.