Hi Bearkeley as no one else has answered your post I will try to although I do not dive here a lot. First question - November in a campervan at Exmouth will be HOT. The average temp is 35c meaning you will get days generally around 40c but you can get days up to 47c in heatwaves which happen a couple of times a month usually. At this point in time the Navy Pier is closed for repairs which is unfortunate as its a brilliant night dive and while things move glacially up there im not hopeful the Jetty will be open. Ningaloo is a shallow reef. You can cut down on your dive expenses by doing some snorkelling around Tandabiddy creek and Doddies bay as it is a fringing reef not a barrier reef so good stuff can be found from shore. My diving destiny started there when I was three years old and a water butterfly floated past which I later was told was a Hexabranchus sanguineus (like all 3 year olds can pronounce that - thanks Dad!). ALL of November - March will be HOT. You are also going to be there at the start of Cyclone season but that doesn't mean you will get a cyclone.
Will the vehicle be 4WD? if yes all the better. You can take the road down from exmouth to coral bay along the dune system passing the old Norwegian Bay whaling station ruins - Ironically now a great place to spot whales in season. Stop off at Turquoise bay for a snorkel before the road leads you out at coral bay. I would not advise buying anything in Coral Bay as the prices are standard perth prices x 4 - also dont bother with the glass bottom boat tours for the same horribly expensive reason. Swimmers and snorkellers often get ear infections (read into that what you will).
Head back out onto the NW Coastal Hwy (Please remember to Fuel up at Manilya as you wont get Fuel again until Carnarvon and Coral Bay Fuel station is also 4x the standard price. Not much noteworthy in Carnarvon, continue down to the turn at Billabong Roadhouse and check out Shark Bay area where you will encounter the dolphins at Monkey Mia and Hamelin pool which is really pretty - if your into scenery take a drive along the road that lead you into Monkey Mia and check out the view from the Zuytdorp cliffs - theres been some amazing bait balls there so you may get lucky if not its still quite stunning scenery and very much a part of our early history - Dirk Hartog island is just out there on the horizon.
Rotto again is horribly expensive but in November you could save a few $ by camping in a tent instead of trying to get a cabin or coughing up the $$ for the hotel.
Rottnest Island | Campgrounds.
It is worth coughing up for a boat dive to do Crystal Palace as the site refers to it as...I just call it sharky cavey thingy place
Shore diving Perth..hmm yes well. There is the Rockingham Wreck trail which is easily accessible from the carpark (gear up in the toilet block unless you like bending over on the side of a busy road) but viz generally tends to be less than stellar. Also dont expect wrecks of the Titanic type stuff - think a couple of small planes and boats purposely sunk and a chicken coop.........seriously!
Rockingham Wreck Trail Shore Dive Directions Perth WA, Howies Scuba
Theres also some good macro stuff on the Ammo Jetty - blue ring octos and nudis are often spotted on the pillars. Point Peron get ready for an 80m walk kitted up over some pretty high sand dunes - you WILL get hot and sweaty.
I would post here -
WA Divers - to see if anyone has any suggestions re tanks as I have my own.
I am also south of the river and will be overseas during november and have a lot of weight that I dont use so id be happy to lend you some - how much are you thinking you will need? Also have a steel 12L tank and a few spare Al80s and a 15L Al tank which all need hydro but happy to help you out.
While you are here also try and take a few days to go exploring the south west - Margaret River wine and foody region, do the wreck of the HMAS SWAN and the Lena etc if you want more
Dive
Back on land if you do head south and do Bunbury/Dunsborough/Yallingup/Margaret river standard tourist route once you get to Margaret River take the Balingup - Nannup Road and check out Pemberton (Tree top walk, valley of the giants, karri forest and gloucester tree) and continue down from Pemberton to Albany along Albany Hwy for some southern ocean love and dive the HMAS Perth with
Southcoast Diving Supplies - Home. If you are lucky you may even get to see a sea dragon down there. They also can point you in the direction of shore diving in the area.
Caveat - the ops I have linked you to are not Ops that I have dived with due to being a spoiled brat and preferring to dive in PNG or similar
but are good as I know people who own them or have dived with them.Hope this helps a little.