I will backup my Multibit folder and install it later.
I presume by 'seed' you mean the random words you need to keep safe to recover your password ?
Yes. They recover your private keys for the addresses generated with it.
How do you guys get along with HD ?
Fairly well. The only disadvantage is that you cannot extract the private keys from Multibit HD GUI.
Or do you just remove/backup the MultibitHD folder to cold storage ??
Moving/backing up the Multibit HD wallet is NOT remotely enough for keeping your wallet safe from hackers. As long as you have the wallet stored in any medium connected to the internet, the wallet is vulnerable to hacking attempts. A cold storage requires the wallet to be generated from a computer free from virus and disconnected from the internet.