You should use key-based authentication to avoid password prompts.
In config.local.php on a developer's machine, that is to say the local perspective the remote environment will usually be either production/live or staging/test, e.g.,
local: dev
remote: live
However, this is how config.local.php should look on the production server--the remote perspective.
local: live
remote:
environments:
dev:
write_access: true
live:
write_access: false
base_path: /var/www/site.com/app
ssh: foobar@123.mygreathost.com
ldp remote will connect you to the remote environment and cd to the base path. It you do not land in the base path, check ~/.bashrc and ~/.bash_profile for the presence of a cd command in there. You will need to comment that out or remove that line if you wish for LDP to land you in the basepath.
The app tries to connect as a login shell, but in some cases this may not be possible. If not then you may find that files such as .profile are not loaded and you're missing some configuration.
See the function default_on_remote_shell for more details.