So this is an interesting question that I think is missing a bit of context. What time period are you inquiring about for "early days?" Because I'm thinking more the 1790s or so, so I will answer this question from that perspective. And if this is the case, they wouldn't have to search far because folks like John Jay, who served as the first Chief Justice of the Supreme Court not only was at the Constitutional Convention of 1787 and participated in creating the new government, but also was a staunch supporter of it (he even write a few of the essays in the Federalist Papers, which were a series of essays designed at promoting public support for the new government).

So there wouldn't necessarily be a reason for justices to reach out to other framers since some of them served on the court itself. However, people like John Jay did continue to have private correspondence with many framers, such as Alexander Hamilton, Madison, Vice President Adams and of course President Washington himself and they did often talk about the new constitution and other political matters.

So let’s take a look at some of the things they wrote to each other. A good example of this can be seen in a letter to President Washington from the Chief Justice of the Supreme Court, John Jay on August 8th, 1793. What’s interesting about this letter is that it shows that this is part of a continued correspondence between the president and the Supreme Court as they try and answer each other’s questions about where individual powers start and stop. So rather than asking about "what was the original intent?" they are more telling what the intent was, rather than asking. Take a look:

Sir

We have considered the previous Question stated in a Letter written to us by your Direction, by the Secretary of State, on the 18th of last month.

The Lines of Separation drawn by the Constitution between the three Departments of Government—their being in certain Respects checks on each other—and our being Judges of a court in the last Resort—are Considerations which afford strong arguments against the Propriety of our extrajudicially [sic] deciding the questions alluded to; especially as the Power given by the Constitution to the President of calling on the Heads of Departments for opinions, seems to have been purposely as well as expressly limited to executive Departments.

we[sic] exceedingly regret every Event that may cause Embarrassment to your administration; but we derive Consolation from the Reflection, that your Judgment will discern what is Right, and that your usual Prudence, Decision and Firmness will surmount every obstacle to the Preservation of the Rights, Peace, and Dignity of the united States. We have the Honor to be, with perfect Respect, Sir, your most obedient and most h’ble servants

John Jay

James Wilson

John Blair

Ja. Iredell

Wm Paterso

So what’s interesting here is that Jay is clearly standing his ground over where he sees the powers are divided that was given in the Constitution. Lines were left intentionally blurry when it was crafted in the first place, so it creates an interesting breakdown over the next decade as they try and figure out their own legal footing.

And what about the constitutional contributors that were still practising lawyers afterwards?

Follow up: did this play any kind of role in the supreme court case James Madison was involved with (Marbury v Madison)?