The ride to Cape York, the northern most point of Australia, is great. Rain forest, tropical beaches, Savanna with huge termite hills and plenty of bumpy dusty tracks.
There are quite some tracks that you can combine. As a cyclist it is worth to stick to the smaller ones (Bloomfield, Lakefield, Old Telegraph Track). At first because the scenery is more interesting but also because there is less traffic making it far less dusty witch can be an annoyance.
The 175km long track through Lakefield NP is often quite bumpy and there are some parts with soft sand. But mostly it is very dusty if there is much traffic. You mostly pass through a Savanna scenery with termite hills, high grass and eucalyptus trees. There are many lakes, swampy and water wholes that attract many fishermen.
There are many simple campsite along the track.
Costal road to Cape Tribulation
This road as paved all the way. Because of that you have to share it with the whole rental car fleet of Cairns. There are some great tropical beaches along the road. Just before Cape Tribulation you pass through the Daintree rain forest.
The Bloomfield Track starts at Cape Tribulation until it meets shortly after Helendale the Mulligan Highway. It is oly 85km long but don't underestimate it. The track is mostly deep in the rain forest - fantastic. There are some streams to cross that should be no problem. The surface is mostly quite good. The real challenge is the steepness. There are some climbs that are insanely steep that you will have difficulty pushing your loaded bike up there. Because it rains quite often around here (rain forest!) the track ca be very slippery.
About halfway you pass an aboriginal community and a bit further Ayton where there is a simple shop and a nice camping. The northern part of the track is far easier.
Battle Camp Road (Cooktown - Laura)
Very varied route. In the east some climbs, flatter in the west. There are some nice rivers to cross. In 2010 they just started to pave the road so it will unfortunately not be a dirt road much longer.
Peninsula Development Road (Laura - nach Archer River)
There is no alternative road for this part. A well maintained track. The surface changes constantly, sometimes it is good, sometimes very sandy. Because all the traffic has to take that road there is quite some washboard. Every now and then there is a short paved section to get some fresh air because dust is the main problem here. Some sections are terribly dusty and as a cyclist you will get the full load!
Old Telegraph Track
The Old Telegraph Track is the highlight of a ride to the cape. A track right out of a Camel Trophy advert. Narrow, curvy, often sandy and right through the bush. There are some challenging river crossings (steep, muddy slopes) and many easy ones. With the bicycle they can all be done. The most well known is Gunshot Creek where there is also a bypass. There are some sandy parts where you will have to push. The whole track is tough but well worth it.
On the northern part of the track there are some challenging river crossings. The last one at the Jardine River is not recommended (deep, crocodiles) so you will have to turn around and go back to the Northern bypass road where there is a ferry to cross the Jardine.
Southern / Northern Bypass Road
Alternative route to the Telegraph Track.About half way it crosses the track. A quite good road but very dusty and bumpy because of the traffic.
Bamaga Road (Jardine - Cape York)
In the surroundings of Bamaga there is quite some asphalt, apart from that it is one of the worst part: often sandy and bad washboard.
Water is never really a problem, you will get to a stream once a day. Only the part between Archer River and Moreton Telegraph Station is dry for 130km.
Shopping can be done in Cooktown, Laura, Coen (simple shop), Bamaga and Seisia (good supermarket). The roadhouses mostly only sell fast food.
The roads to the cape are only passable during the dry season june to september. The further north you get, the hotter and wetter it gets. Wind mostly blows quite strong from southeast, cycling north is easier.
If you don't want to cycle up and down the peninsula, you can fly back from Bamaga to Cairns or there is a cargo boat that travels to Cairns once a week.