Not sure if this is where I should be posting this or not but here goes...I'm planning a bicycle camping trip with my kids ages ranging from 3 years to 17. We plan on doing the "petit train du nord" bicycle trail (abandoned railway). From Mont Laurier down to St Jerome Quebec. It's only 200km and we plan on doing it over five days, taking our time and seeing the sights. I have a few questions as I have never endeavoured to do something like this but have always dreamed of it.
1. Has anyone on here done this trail before? I've researched it to death but just wondering if there are any first hand accounts of things I should see or do along the way?
2. We are all using our mountain bikes for this trip (all older model Norcos) that we all find comfortable to ride. The trail itself is I belief 10% paved 90% crushed stone but from reports I have read parts of it (not much of it)are not well maintained and are pretty rough from its use being very popular. Just wondering if I should invest in a slick touring type tire or not? I want to make the trip overall as easy and as enjoyable as possible for the kids. I just fear that the slicker type tire will be useless on those rougher parts or even on the stone as I am not familiar with them at all (and I really don't know how rough the rough spots are) or prone to punctures or flats given the gravel. I also planning on going slow and smelling the roses anyways so would having the knobbies versus the slicks make that much of a difference?
Thoughts? Advice? Anything else I should be considering?

Thanks,
Sean

Also of note the three year old will be in a trailer the other three kids will be pedalling.