Depending on tides, you could try Telegraph pool if the tides are larger, its close to the upper tidal reaches. Or closer to the mouth down Pelican pool if tides are smaller. If your goin thru Broome drop in to a tackle shop and grab a mud map off them, a mate got into a few salmon down Pelican way a month or so ago.

I think you are headed for some disappointments with the knowledge you curently have.

The Fitzroy is a big river and there are many places to fish. Do you realise you will be going at the worst time of the year ? Not sure where you would get access to target Jacks as I never caught any there although im sure they are around in the tidal reaches. Most people fish the fresh water pools around Telegraph Pool or Lange crossing for Barra.

Telegraph pool is the last well known tidal pool and will take salt water from around the 7.5 m high from memory. Pools above telegraph are fresh.  Tackles shops in Broome might have maps to direct you in there, I forget the turnoffs etc ....really guys , not wanting to burst your bubble but there are many better options for this time of the year much closer to Perth.

Almost 2500kms is a long way !! But if youre determined to go, you will need to put in the hours and you could catch a couple of Barra. People dont target Jacks or Crabs  but that doesnt mean there arent any around , especially if you get a warmer patch of weather. Jacks in this area are usually caught in the smaller creeks further up the gulf or even Willie creek close to Broome. 

This time of year is not good for productive fishing in the Fitzroy, coldest time of the year and the barra will be very quiet. However the further towards the mouth you go the better your chances will be, but also the more likelyhood of coming across the snap snaps and there are a few there. I've only caught barra there and no jacks. If your after local knowledge call in and see the folk at the Willare Bridge roadhouse. I'm not saying dont go either, but going much earlier in the year would be better. Try Pender Bay for jacks.

yeah Pender Bay is great for Jacks even sightfishing for them on the first of the run in tide !! and awesome Bluebone as well at the bays entrance !  But if its Jacks you want , the Exmouth Gulf is also another option ... haha.. probably not what you are wanting to hear guys, just think there are much much better options for you  than the Fitzroy River.

ohh and mega Mackies out the front, huge schools of Northern Bluefin Tuna, Sails, Queenies, GTs and whatever you want bottom fishing. :)

 A lot of helpful info guys much appreciated. Is there access to the river mouth? That sounds like the go. I knew it wasn't the best time of the year but didn't realise it was really bad. Iv only got a 2 week window to fish and can't be bothered with the big boat. Iv fished fitzroy once in September and caught 2 jacks and a few small barra over 2 days in some pools and did no good in the fresh part. I will definitely pull in the road house and ask questions and grab a map from the fishing shop

Go to google earth or something similiar and would see why im not advising it. It big open flat country down in the tidal reaches and when you consider up to 13m of water can rise and drop in 6 hours ...a lot can go wrong. Even most locals would never consider trying to go deep into the tidal reaches ..just too dangerous.   One untimely underwater log in the strong current and you will be in the drink with the crocs. If you fish Telegraph pool I would expect you might get a couple of barra for a hard weeks fishing ...if this is ok for you,give it a shot . but, You will be passing many great fishing creeks along the way north where u can catch plenty of Jacks, crabs etc and then also have the option of blue water fishing when the tides are fuller and the creeks go quiet.       

I have a feeling you might have to contact a station owner now to get into the Fitzroy I read a bit about it in the North Australian FishFinder If i was at home and not on night shift I could give you a number I will look tommorow and post it for you .I used to go to the Fitzroy 2-3 times a year when I lived in Hedland and fishing live baits at night in Telegraph pool always produced some big fish and threadies too ..cheers