Toby, it's been a number of years since we've last been but we've attended the festival 3-4 times. Yes, it's quite a ways out of town at Birds Hill Provincial Park, which allows the stages to spread out without audible music overlap.
We stayed in town so can't help you with campgrounds. There are two: the "Festival Campground" is your choice if not allergic to later-night revelry, including folks makin' music. I'm told sometimes some of the performers wander over there for impromptu jams.
https://www.winnipegfolkfestival.ca/festival-info/camping/
The website pretty much has all you need to know.
https://www.winnipegfolkfestival.ca/experience/how-to-folk/
LOL, the first years we went there no alcohol allowed on the grounds so we tailgated in the parking lot (along with lots of others) while fetching our warmer evening duds. They'd added a tavern the last time or two we went.
Clothing: prepare for anything. One year it rained a lot and was really chilly but temps were in the 90's on another and we were all running around with spray bottles and whatnot to try and cool off. Another year they'd had torrential rain before the fest that turned much of the ground into a muddy mess: was happy I'd brought my rubber boots!
Pay attention to the Tarp Shuffle! This is new since last we went and everyone made a (dead run) beeline to the main stage grounds first thing in the AM to anchor a ground tarp as close to the stage as possible; that was your personal space all day/evening. They've probably adapted a lottery-type system to make things a bit more equitable.
Chairs: As instructed, regular-height chairs are only allowed on the outer edges of the stages. Otherwise, lower beach chairs are allowed or sit on the ground. If you bring beach chairs- which I recommend if the ground is wet/damp - you'll be carrying them around all day if wanting to sit so buy the lightest weight you can find. We left ours on our tarp now and then during the day and opted just to stand on the fringes at the assorted daytime stages.
Chairs no taller than two feet and 8’x10’ tarps are welcome in the seating area.
There is no wifi.
Yes, bring bug spray but I honestly don't remember them being a huge problem after dusk. What we HAVE experienced were some pretty cool Northern Lights!
See the map for the festival's layout:
https://www.winnipegfolkfestival.ca/festival-info/
Their performance lineups used to be great: in addition to the performers we knew, we always picked up new folks/bands to love! Honestly, it was always fun even when it rained. Hope I've given you a bit to go on?
Oh, and they traditionally close the last night's concert with "Goodnight Irene" and "the Mary Ellen Carter"; that last a much beloved song from much beloved, sadly gone, Canadian folkie Stan Rogers. Learn the words to both so you can add your voice to the other thousands :O)
"Rise again! Rise Again! That her name not be lost to the knowledge of men! No matter what you've lost, be it a home, a love, a friend, be like the Mary Ellen Carter, rise again!"