I've fished fresh water all my life. This year for our wedding anniversary, we're going to be staying in an RV park on Galveston Bay. As for gear, I've got a Cabela's Salt Striker combo. It's spooled with a heavy braided line, though I don't know the test as it was on there when I bought it, used. Today at BPS, I picked up 45# test steel leaders and a Laser Eye Magnum Rattle Shad. I hope that's enough. Any advice would be greatly appreciated.

Gold spoons, shrimp tailed jigs (alone or under a float), topwater lures, and suspending lures will all work. When I really want to catch fish, I use bait. Shrimp under a cork will get trout, ladyfish, and other species. Shrimp on the bottom will almost always get hit by something. Mullet will catch redfish and big trout. Live or fresh dead is best. If you catch a ladyfish, cut it in cross sections and throw that out on the bottom. Be careful with hardhead catfish and stingrays. Good luck and let us know how you do.

I almost bought a Spook top water

Any bass tackle is more than adequate to catch any red trout or flounder you come across.

Saltwater can mean a lot of things. Wading or drifting in a bay chunking plugs and tails for trout and reds is a completely different animal than soaking cut or live bait in the surf for reds, sharks, drum and gafftop. I kind of gather it’s the bay type the OP is wanting to do.

I see the OP mentioned steel leaders. If using lures while wading or fishing from a boat in the bay is the desire, then I’d nix the steel leader and go with either a short section of nylon mono or fluorocarbon for a leader or just tie the lure directly to the braid.

Don’t take your best bass reel, especially low profile baitcasting reels, into the saltwater as it will likely never be the same, unless you are extremely careful and very, very good with reel breakdown and maintenance.

Shuffle your feet. Stingrays ruin fishing trips.

You can do a lot of damage to trout and redfish tossing a paddle tail on a 1/8 ounce jig head. Topwaters like the spook the OP mentioned are great searching plugs. Spoons can too be deadly.

Saltwater Fish like freshwater fish generally aren’t random, they all key on structure and/or forage. Current comes into play a lot in the salt. I like to fish looking for clues from the forage or predators and try to infer what the structure is. There’s often a pattern you can pick up on. But, nothing wrong with tossing a topwater or spoon out and seeing what might be there if the clues seem to be absent. Can’t catch anything without your line in the water.

I'll be mainly fishing from a dock/pier. It's just something to do while I'm there.

Fished Galveston Bay in San Leon. Caught 3 hard head cats with live shrimp under a cork the first day. Once the sun went down, caught several spotted sea trout on a swim bait. Ended up with probably 10 caught and just as many short strikes. None were keepers. Another day I caught 2 more trout, both undersized. Couldn't get the flounder to bite.