Hi.
I’d like to access all parts of my Home Assistant-system from outside of my home network.
To be able to do this, I have to open ports in my home firewall for HA itself, for the hass.io configurator, for node red and who knows what else?
I don’t like doing that, since every added open port reduces the network security.
Is it possible to solve this witout opening a lot of ports?
Yes. Look into a VPN or some Remote Desktop software.
Like @silvrr look into VPN. I have my frontend exposed but all other stuff is done through a VPN connection.
Any open port make me nervous 
One port works fine for me, you shouldn’t need anything else. Otherwise VPN.
Some routers, Netgear and asus for sure, have openvpn server function built in.
I use it and have no open ports
nginx is another option other than VPN.