Doc is right about the public transport being pants. Tant if you let us know what days you are wanting to travel on (eg up on Friday back Monday etc) Then I am sure something can be arranged about collecting from a train station or the like. I can certainly take you if the times etc tie in and we can meet somewhere. Although with it being during the school time I will need to head home on the Sunday if I have my daughters with me, so they can get to school on Monday. This may be a consideration for a few people.
I will have my canoe and we are right on the shore of Loch Achray so basic instruction can be given. I have two childrens and three adult PFDs so enough to share with other canoes also I have four adult paddles and two childrens. Sandbender should have his canoe by then and there may be others.
Regarding exploring the rest of the forest drive I have to point out that there is a one way system for cars. The youth camp is situated near the end of the drive. The drive is about 7.5 miles long and the speed limit is 10 miles an hour so realistically if you want to go to another part of the forest drive in a car you are looking at almost an hour of car travel, even if it is just 5 minutes down the road. Not really an issue if you want to go to another Loch for a longish canoe trip but a factor of you just want to nick down the road for a bit of fire wood. However, that said this one way system is only alicable up till 6pm when the forest drive is shut. After then we have the road to ourselves, pretty much.
Facilaties are going to be more basic than at Sandbenders. I do not think there is water but will check with Stuart. Toilets are up to us to supply or dig and food / cooking is also our sole domian.
Regarding what to do I would suggest that anyone that has skills etc that they are willing to share then post them here and we can see what options we have. For my part, as I have said, I am willing to do some basic instruction in using an open canoe.
It may also be useful to say what we would want to see. For my part I would like to see some spoon carving with basic knife and spoon knife as it is an area I enjoy. Firelighting from friction I can't see enough of. Also given the number of younger children we could really do with a project to keep them interested.
As a reminder here is a map of the area. Sorry it is a little big but I am at work and can't resize it from here.. The site we are talking about is the youth camp at the top (circled)
Oh and regarding communication the site generally gets pretty good mobile phone coverage. That applies to pretty much all of the forest drive.