You can override that in your code like follows (replace with desired value and name of your config file):
Config.DEFAULT_CONFIG = {
'data_path': '/tmp/fastai/data',
'model_path': '/tmp/fastai/models'
}
Config.create('/tmp/myconfig.yml')
Config.DEFAULT_CONFIG_PATH = '/tmp/myconfig.yml'
In subsequent notebooks you just need to set the DEFAULT_CONFIG_PATH to your config file.