How can I cancel my player user and delete my base?

I think deleting Personal Data Info might do it, but I'm not sure; there is the option there on the sign post near your main base. But I'm not sure if it removes it from google play account.

You can't currently delete a game account. But if you don't log into it for a long time then it will be automatically removed. This is according to the in game help. It doesn't say how long it needs to be abandoned for before it is deleted though,