You will have a great time camping in Queensland. Having said that you may find it very hot as Feb is the hottest time of year with temp's getting up in the high 30's. Doesn't sound like much but combine that with 90% humidity and it can be very hard to cope with. Spring for air conditioning in your camper. You'll be very glad you did.
The below site
http://www.epa.qld.gov.au/parks_and_forests/find_a_park_or_forest/
has the list of National parks where you can camp. The permit fee's are different for each area but it is a good site for locating camp sites. Be aware though that some of these are only accessible to 4WD (SUV?) and your campervan insurance wont cover you if you venture off road.
Some places that you will want to stop.
Noosa - Centre of the yuppie beach culture. Check out the walking in Noosa National Park, spectacular views. Then head over to Sunshine beach if you want a little surf for a swim. If you have time head up the road to Inskip Point - Turn off just before Gympie. Camp on the beach accessible to camper vans. Plan to spend at least two days though its a bit of a drive off the highway.
Hervey Bay- Although whale watching season will be over its not a bad little place. Good to collect all the info tourists need
Town of 1770 - Definitely worth the long drive off the highway. Near Bundaberg. Beautiful little spot. Ask the locals where some of the best out of the way spots are and you will find deserted beaches and great fishing. Good jump off spot for Lady Musgrave Island for some diving.
Yeppoon - Near Rockhampton - Right on the water and shouldn't be too crowded. Can get very hot at that time of year. Great place to just flex out and soak up some Aussie small town culture. Good fishing. From there organise a day trip out to Great Keppel Island. Fairly inexpensive and absolutely beautiful. Its a tourist resort but you can hire the equipment and have a fun day and its a lot cooler than the mainland.
From Rockhampton there is not much until you get up to Mackay unless you want to explore unnamed roads which can get you some fabulous experiences.
My recomendation would be to head inland and get a taste of the outback. Head out to Emerald and do some fossicking for gemstones.
Then if you have time head out to Longreach and go to the Stockmans Hall of Fame. Its propably the best town to get a real taste of the outback with the School of Distance Education, Qantas museum etc.
If you too short on time go back up through Clermont and if your there on a Friday go on the Coal Mine tour. Its free but its $6 to go to the museum which is on the same tour. You'll need to book about a week in advance. Then continue to Mackay. Nice town but a bit boring. Head instead to
Airlie Beach - Lots of international travelers all soaking up the sun and atmosphere. Bit of a party town. This is the beginning of the Whitsundays, an Island area that can be beautiful.
Then to Townsville which is a great town, lots to do and see. go over to Magnetic Island. You can access indigenous tours etc if that interests you. If you didn't take the inland diversion then take an over night trip to Charters Towers for a little taste of the inland. Stop at Ravenswood and check out the Imperial country pub. A great example of a gold town pub. Its almost a ghost town now with only about 100 residents.
From Townsville head up to Cardwell. One of the best kept secrets on the North. Nice friendly little town with access to lots to see and do.
Then on to Cairns which I would say is one of the most over rated cities in Australia. Having said that tourists love it.
A great site for road travellers is
http://www.racq.com.au/travel/trip_planner
This is the local auto club site which has a trip planner which shows how far the distance is between towns. Handy if your trying to work out how long much time you should allow. Two weeks will be plenty of time. Search the web for Camping Queensland and you'll get heaps of info. Camping on the roadside can be dangerous but if you stay locked in the van you would be fine. Hot but fine!!
Well hope this helped. Have a great trip.