I have ridden a few sections of the ECG as part of a different tour. I have 45+ years and 75k+ miles of loaded touring experience. I will not ride their route again. Each section to me was highly unsuitable for touring, or even most cycling. Very heavy traffic (25k AADT), little to no shoulder, high speed, etc. Not enjoyable at all. If wanting to ride the east coast, I would look at ACA's Atlantic Coast Route. While not idea due to being in a very densely populated area, in my opinion, it is far safer than ECG.

Whatever you decide to do, I wish you a wonderful and safe tour!