Hey Rick,
If you haven’t figured this out I can give some advice. In order to access your Pi from over the internet you need to get the Public IP of your internet connection. Go to https://www.whatismyip.com/ on your computer to get your Public IP. You can then sign up for a free dyndns service like noip or dynu. That will allow you to create a internet facing name which you link to your Public IP. Reason for this is depending on your internet connection, your Public IP will change every 24 hours, unless you are paying for a static IP, so having that name will prevent you from losing access as it will update each time your IP changes.
The next step will be to open/forward the port you access your Pi on, from your router. Google your router model and port forwarding or have a look in the manual. You need the username and password for your router but based on your msg above you already have this 
Best practice is to change the port to something that is uncommon to make it more secure, not sure where to change the port Mycodo runs on but maybe Kyke can chip in, haven’t looked but I’m sure it’s possible.
So to sum up, forward the port from your Router to your Pi so that it’s open from the internet.
If possible change it to something secure.
Then lastly get your Public IP and setup a Dyndns account. Just google free dyndns.
Once you have created a dyndns account and linked it to your IP, you need to set this account up on your Router. Most routers will have an option to setup a dyndns account. it will ask you for the hostname, username & password.
Once that is done you should be able to access it from the internet. Make sure you have a secure password setup for Mycodo as well
Cheers