Gulf Coast where?
In south Texas, beaches at Padre-Mustang islands, birding in the back bays. Fishing either on the beach or in the bays.
More to the north in Texas, Galveston island, beaches and bays, historic sites from colonial eras forward, including military and hurricane stories. WW2 aviation museum, drilling rig museum in Galveston.
Big gap from Beaumont to Lafayette where it is hard to reach the coast, but fisheries, fish farms, alligator attractions.
Between Lafayette and New Orleans, you get to cross one of the Mississippi's old outlets, bayou country. This is a great place for getting into a boat and exploring the swamps. It is also a place to have a look at the offshore oil industry, operating out of Lafayette. The area also has it's own subculture, languages, cuisine.
New Orleans is a big attraction by itself, people visit for weeks and keep coming back for more.
Into Mississippi, beaches south of the bays (but still on Mississippi Bay rather then the Gulf) and casinos. Into Alabama, more beaches at Gulf Shores, major port city at Mobile. USS Alabama memorial.
Into Florida, best beaches on the Gulf are between Pensacola and Port St Joe. Naval Aviation history at Pensacola, resort living at Destin.
Much beyond Carabelle, it is a bit difficult to reach the Gulf Coast again until you get past Spring Hill, the coast is beyond the wide forests and wetlands, with a few road running west to small coastal towns from US-98 or US-19.
From Spring Hill, you can follow the coast, or close to it, all the way to Venice. History of sponge industry at Tarpon Springs. Well developed retirement living Dunedin to St Pete, and Bradenton to Venice. Ringling home and circus museums in Sarasota.
Roads then go inland to Fort Meyers (Ford and Edison winter homes), then back out to the coast to Naples. Naples is about the end of the Gulf Coast you can visit, from there to the south it is Everglades, can't tell where land ends and water starts, and can't really get near the Gulf.
There it is, Corpus Christi to Naples, 1400 miles of Gulf Coast. Another 160 miles from Corpus to Matamoros, but as with some other places along the coast, you can't really get to the coast.
My preference is for the New Orleans to Mobile Gulf Coast, and a close second for what Florida calls the Nature Coast (Cross City to Spring Hill) where you don't really get to the coastline but you learn a lot about coastal wetlands.
If you are a beach person, I suggest Padre-Mustang Islands, or the middle of the Florida Panhandle beaches, around Destin to Fort Walton. Urban explorer, consider New Orleans, Houston-Galveston (Houston is as much on the coast as New Orleans), or Tampa-Saint Petersburg. Even coming from as far as New Mexico, Fort Walton is less than a day further than Corpus Christi.
Tom Test
Itasca Spirit 29B