It has been possible to walk (or bike) through Prince Edward Island since the Confederation Trail was created on the decommissioned railway line, sometime in the 1980s.
The main trail is 273 kms from west to east from Tignish to Elmira, with a number of branch lines for a total of 410 kms. To walk from tip to tip, walk from North Cape then along a not too busy road to the small and pretty town of Tignish (about a 15 km distance), then start on the Confed Trail; on the other side, walk from the railway museum in the community of Elmira to East Point after the Trail ends (about a 10-15 km distance). (Or you can always walk east to west...watch the sunsets, not the sunrises!) Traveling from tip to tip of the Island will garner a certificate for doing so. The trail is mostly flat but has gradual grades and meanders through beautiful landscapes and alongside farmers fields. It's easy to see wild animals and birds, though some, like coyotes, are shy and stay away from people.
Food is not expensive on the Island if a person knows where to look. Lobster is at this time, for here, a bit pricier than usual, but far cheaper than other places. We also have world class oysters, mussels, quahogs, clams and other shellfish, as well as other seafood, delicious produce and more. With a welcome influx of people from across the planet we have restaurants and cafes providing international cuisine. And with the top cooking school in the country located in Charlottetown--our capital city--we have such exquisite food here that we are now known as The Food Island.
No one wild camps here; there are enough campgrounds. In many places wild camping (camping in general) is prohibited: the national park and the provincial parks, for example. Campgrounds close in September, generally soon after Labour Day, so accommodation should be sought at still open motels, hotels, inns, B&Bs in the autumn. In many cases the only places open after the summer tourist season are in the larger centres, such as Charlottetown, Summerside and Montague. "Larger" is a relative term here...
The trails on PEI are set up for day users who travel to them, walk/snowshoe/XC ski them then go home. The Confederation Trail is used exclusively by a snowmobile association in the winter and walkers are not able or allowed on it.
Winter is not the time for long distance and multi-day walking. Our temperatures can drop well below freezing (usually between -3/-11°C) and with the windchill, can make it feel like -25°C or colder--it can be dangerous to be outside for any length of time. Plus with the average 290-300 cm of snow we can get, trails are not groomed and in some cases when we get a decent snow storm, even roads can remain unplowed for days. https://peisnowstorms.blogspot.com/2015/02/
Our summers and autumns are spectacular.
Flying to Europe from PEI is cheaper than flying pretty well anywhere in Canada, sadly. It's faster to fly to London and Paris than to Calgary, Edmonton or Vancouver. Flight costs are based on population/number of people who fly; we have a population of 150,000 and not all of those people travel. And in the winter we have far fewer people flying in than we do flying out.
We are far more than just Anne of Green Gables. We are also chocolate covered potato chips, red clay, lobster, music, theatre, the location of the creation of the country of Canada, many cultures of peoples, including our First Nations, the Mi'Kmaq, beautiful beaches, and much much more.
If you want any information about walking on PEI, contact Island Trails: https://www.islandtrails.ca/
If you want any information about PEI, accommodations, etc, have a look at tourism PEI's official (government) website: https://www.tourismpei.com/