Jane's project is achievable, but requires a large time investment.
The first choice Jane has to make is what material the book will be written on, which is dependent upon her definition of book.
Parchment, such as vellum, requires the hunting and skinning of animals. While rabbits would be easy to catch, their hides are small and Jane would need a large number of rabbits to make her novel, dependent on how small she is able to or willing to write. A single calf, on the other hand, can yield about 3.5 medium sheets or double that if folded. However, if Jane is not willing to buy calves from people, she will have to start a cattle or sheep ranch. She will require tools for skinning. The skin has to be washed by soaking in water and then dehaired by soaking either in a fermented vegetable bath or in a lime bath. Both of these should have their own separate soaking places to save on time, so at least two pits or vats are required. A frame is also needed for stretching out the parchment after it has been dehaired. Any remaining hair would be removed by a knife at this point. From skinning to writing-ready parchment might take up to two weeks depending on the temperature of the dehairing bath and how quickly Jane learns the process.
Tablets or steles are easy in terms of resources, but would require a large amount of space to make a novel. All Jane would need is a source of stone, clay, wood, or wax and she could get started. Clay tablets can be sun-dried or fired in a kiln with the later being more durable, so Jane might need a kiln. Wax tablets can be wax covering a wooden tablet and have the benefit of being editable--simply heat up the wax to about 50 degrees Celsius and start the tablet over again. But Jane would likely need to take up beekeeping. For steles Jane would need a method of moving the stones or wood into position. All of these would benefit from being housed in a cool, dry building.
Paper can be made out of a variety of plant materials. While wood pulp is common today, flax, cotton, hemp, bark, bamboo, and papyrus sedge are other materials that can be used. While papyrus might be one of the easiest papers for Jane to make, it doesn't last long in the climate of Western Europe. Xuan paper and washi, made from the bark of trees, such as mulberry, are probably Jane's best bet for papermaking. First Jane would have to collect the bark and allow it to dry. The bark needs to be pounded and washed--the order depends upon the type of paper. Bleaching may also be done, though Jane need not use the chemical, as traditional bleaching involves the action of the sun and water. A screen, either of metal or bamboo, is needed for forming the sheets. The sheet can then be pressed by another screened frame (like a mould and deckle) or placed on a heated stone. Winter is a better time for this papermaking because it reduces the chance of rot. This is a simplification of the process. The benefit of this process is that Jane would be able to travel to China, Japan, or Korea and be able to find places where traditional papermaking is carried out and possibly become an apprentice.
Bark or bamboo can also be a decent writing surface in itself. I once wrote a poem on some birch bark. Bones could also suffice. It really depends on what Jane means by book.
Once Jane has figured out the material to use, she can then figure out what she will need to write with.
A chisel and a percussion tool, such as a mallet or hammer, would be required if she intended to carve her novel into stone or wood. These could be fashioned out of stone, though if she was willing to take the time and effort to smelt copper or iron, then she could use metal tools.
A stylus would be required for the clay or wax tablets. Any material would suffice as long as it was pointed.
A brush and paint could be used with a variety of surfaces. For instance, Jane could paint her novel onto steles or tablets. Or she could chisel out the words and then fill them in with paint to make them stand out. Various animals could be used as the source for the bristles, including sable, rabbit, hog, ox, and goat. Egg tempera is one form of paint that would be easy to make.
A pen or brush and ink could also be used with a variety of surfaces. A pen can be made from reeds or quills, both of which wouldn't be hard to get. Some sort of knife would be required to make these pens. Inksticks are made from soot and animal glue (made from the boiling of animal connective tissue). To get the ink from an inkstick, it is ground on an inkstone and a little water added. Iron gall ink, which can be used with pens on parchment and paper, would be another possibility.
The other consideration for Jane is how to collect the book together. Steles, for instance, would be stood in a field or room. If she went with paper or parchment, some sort of binding would be needed. Thread could be made from cotton, silk, or linen. Bone could be used for the needle. The cover could be made from paper, leather, parchment, wood, metal, or a combination of those materials.
This process will likely take Jane several years if not decades. Not only will she need to learn a variety of skills, but she'll have to deal with growing times for plants and/or animals. And not all of what she produces will be usable, as she may have a tool break (possibly ruining what she was working on) or have a batch of paper ruined because of mold. When done right (and stored in the right conditions) many of these materials will last for hundreds if not thousands of years, so Jane won't have to worry about her materials spoiling on her once the process has started. She'll just need to get the requisite level of skill in several different areas to be able to make the quality of material she needs. And her desire to make all her tools will be one of the biggest time sinks, as she'll need to learn skills that won't help her at all with actually creating a book and spend time making tools to make better versions of those tools to make the tools she needs to make books. Because it involves such a long time frame, the biggest struggling point will actually be sticking with the project. Jane will be spending a long time with not much to show for her efforts, which might be very disheartening.
