Create a Gmap with Views that connects locations of different nodes I am looking for a way to make some sort of roadtrip website. 

The idea is to use two node types: a parent nodetype "Roadtrip" and a child nodetype "Day". The user can create a Roadtrip and add a different Days to the Roadtrip. Every "Day" have a location field that needs to be filled in.

Then, I want to use Views with a Gmap display that I show on the parent Roadtrip node page using contextual filters. On that map, I want to show all the locations of the different Days and connect them to eachother in ascending order by publish date. So visually, you can see which trip someone made in how many days.

I am quite familiair with Views but can't wrap my head around Gmap and it's API so, anyone an idea how to achieve this?
This answer is for D7, you'll need the folowing modules: entityreference to relate both contentypes,
 geolocation_views only D7, it displays several nodes in a single map, geolocation, and simple_gmap, this one is for for users to enter city name in a text field, handy tutorials: https://www.youtube.com/watch?v=hdzembWMgPc and https://www.youtube.com/watch?v=Pc0xPiRBb54 and https://www.youtube.com/watch?v=FVvKJlq4Wo8, you will end with something like this, each mark in map links to your day-node, enjoy.