Advice of midway stop between Calais/ Montpellier

Trayci

Can any of you lovely people help please?

We are planning our summer holiday and intend travelling from Calais down to Montpellier but obviosly can't do it in one go.  

Where would be ideal for a stop over? And do you have any recommendations of sites?

(We are two adults of 40 and no children to keep happy.)

On our way back we shall be stopping in Loire and traveling back via Le Harve.

Thanks in advance for any help.