At this point, anywhere. Once you get to a point that things are being referenced that you haven't read, then you go back and find the referenced issue.
You also might want to specifically search for a series that had a limited arc so there's a finite amount of issues to read through.
And if you don't care about "cannon", I remember loving the "What If?" and "What The--!?" series. Very much has the vibes of kids talking about "What if the Wolverine was also The Hulk" ...