Have only been there as a car tourist, last time already a long time ago, 15 years probably, but I can confirm most of what others have said.
Mosquitoes comments are accurate, but not really any different than areas around here, but could be shocking to non campers or those from non mosquito-ey areas.
Singing sands Beach and folks jumping off into the current, I remember that clearly.
One other clear memory, "Islanders" are generally very friendly, drive super considerately and pretty darn slow often (geriatric slow)
Will PEI be that different than the other Maritime provinces, maybe not, but will still be a neat coastal experience.
I've thought in the past about biking in the Maritimes but in the end preferred going to France or somewhere more exotic for this Canadian. ( But probably because I went there as a kid a bunch of times and then drove out there with our kids, a lot of driving)