I'll be hiking the Wonderland Trail this September. Can't wait!! Just have to stop drinking so much homebrew...
Tom, any pointers/lessons learned from your trip?
Sorry this is so long, feel free to ask questions. I might not have the answers, but I can try.
If you are an experienced backpacker there is nothing you really need to know. Just get the book "Exploring the Wonders of the Wonderland Trail". There is typically plenty of water, the trail is well marked and plenty wide for one person, and you probably won't hike more than a five or six hours without seeing some people.
But since I have no idea how much experience you have with this kind of trip, first some general backpacking stuff. Pack light, but don't skimp on the necessities. Bring some kind of insulated underwear, and raingear is a must. First aid kit, knife, fire starter, the usual emergency gear. You're not allowed to light fires, but an emergency is an emergency. Bring line to hang your food, don't keep it in your tent! There are bear-proof poles at all of the campgrounds. Bring your own TP. A warm poly sleeping bag, not down unless it will keep you warm when it is wet. Comfortable shoes to wear around camp. Broken-in boots. Spare clothes in a dry bag. Plan on everything getting wet. It is generally very safe, but be smart, at times you will be a couple of days from help. Bring garbage bags for your trash, you can drop stuff at the ranger's stations.
Figure out how much food you're going to need. I planned on 3500 calories a day and found I just couldn't eat that much so I had way more food than I needed. By the time I figured that out I was several days from a ranger station where I could dump food. Which brings up the next point . . .
Decide if you want to carry all of your food, or mail caches to the ranger station. I carried mine, but some hikers I met made the point that you need to mail it well ahead of time to make sure it will be there when you need it.
Figure out how much fuel you'll need, add a fudge factor, and just take that. I way overestimated (probably because I couldn't eat as much as planned) so I was carrying more than I needed. But a hot breakfast cannot be overrated.
Don't stop to cook lunch or you might end up hiking in the dark. Bring a headlamp and spare batteries.
Know your water needs. Bring a good filter and a camelbak, mine was 3 liters which was enough except for one time. Usually I would pass more than one water source before my water ran out during the hike I also brought a 5 liter collapsible container to hold water at camp, I found it very useful. I could filter enough for cooking and to fill up the camelbak the next morning. There is a lot of water along the trail so it is generally not a problem.
Expect to hike in the rain. It was beautiful the whole time I was there with the exception of the last day (Sep 22nd I think), but it's not always like that. I've heard of people who hiked it when it rained every day.
There are a couple of days when gators were a really big help - they're light enough I think it's worth bringing them. On another hike when I didn't have them and walked through a similar area (wet leafy plants overhanging the trail) my socks got super wet and my heels blistered and tore, but I didn't feel it until later and then it really hurt to put my boots back on the next day.
Long pants with zip off legs to make shorts are great - for me it was often chilly in the morning and hot later in the day, and taking boots off to change into shorts would have been a real pain.
Get current trail maps and pay attention. The trail is very well marked and not especially precarious. If it seems iffy, backtrack a bit and look around, you may have missed where they rerouted it.
Don't sweat the glacier crossing after Summerland, follow the footprints and it'll be fine. Use the toilet at Indian Bar, the view is amazing.
Like I said, it is generally very safe so there isn't much to worry about if you take the usual precautions. Relax and have fun. And bring a camera, it's beautiful!
As always, take nothing but pictures, leave nothing but footprints.