Have made that trip several times.
Worst part is Mississippi River to Galveston, then Galveston to Brownsville. Even now I won't do the southern leg and I am from there.
I won't do it again unless in a restored PT boat or Cigarette boat that belongs to someone else and I have their credit card.
It is straight for miles, with nothing but countryside. You will encounter more barge traffic than you can imagine. Bald eagles, Bob cats, coyotes, deer, cows, etc. Few places to stop, no place worth going for.
It is truly desolate. One stretch at night had so many lightning bugs, they literally illuminated the ICW at night, millions.
Should have supplies and fuel for one week.