I would consider looking at two separate problems. First, you need to hire something to get the trailer to the site. Second, you need a much lighter, faster, more comfortable, less expensive, more practical boat to ferry friends and supplies. Like a garvey.
It is not safe to put that much weight that high on one of those modular barge sections, but two or three sections would be safe. The barge looks a lot like a Flexifloat series H-50 modular barge section. Except that company is in Houston TX. There may be other properties on the lake that had to deal with a similar situation so a local marina or building contractor might know where to go. There may be a local outfit similar to Kehoe Marine Construction that can ferry the trailer. [searched 'Canada modular barge section'] Or find out who built the barge you found and contact them.
