Anyway I also have two different development environments.
One of them is a Linux box where I use Apache and it is quite similar to
the deployment environment but needs a few different config values.
The other one is a Windows box where I run the script and use the
built-in web server.
Can I have more that two environments ?

you can set your environment with:

"export DANCER_ENVIRONMENT=production"

if you use plack, Dancer will use the one set by plack. To configure plack environment, you can use 

"plackup -E production"

or 

"export PLACK_ENVIRONMENT=production"