6'3" is not " too deep" for the ICW
, but you will certainly have to watch the tide in areas.
Most of the US east coast
can be done in offshore
You can get the "Waterway Guide" which will list problem areas.
Summertime is mostly mild weather
and sea conditions.
I have done the US east coast
both on the ICW and offshore
, with a 6'3" draft
I did run aground in a few areas in the ICW.
Much prefer the offshore route
In the US you can buy a subscription to BoatUS or Seatow for about $150 a year, and they will come assist you if you run aground.