It's a good idea to have a backup of the node somewhere in case the main node goes down for some reason.
So I clone the whole droplet
including the wallet.dat and start the walletd in the cloned node? The two won't interfere wrongly with each other?
No. Just have a backup of the wallet ready in case your droplet goes down. If it's a droplet, you probably don't have to worry about it too much.