It is not a crock, and anybody who has ever studied history seriously would tell you that. The John Adams led faction was regarded as small, many of the members of the Continental Congress were still fulfilling contracts with british companies, traveled thru areas controlled by the brits, met with legislatures (who appointed them) who in several states were still loyal to the crown. Reps of the congress still met with reps of parlaiment in an effort to resolve further conflicts. While the nut job King George had a fixation, parliament carried a bigger stick.
One of the reasons that even the discussions were kept quiet, was the risk that existed for so many members. If not to them, to there prperty and there family. Yes Adams, Franklin and Washington were dead meat, but they were regarded as extremist rebels, not in the majority. And there is evidence to suggest they weren't. I don't recall who the member was who was appointed to Congress at the behest of a british officer, but the member was a signer, and I'll wager the officer had some splainin to do.