The Hilliers of the world aside, proper communications, particularly acknowledging the rural mindset, might alleviate some of the concerns. Proposing a corridor that will be isolated out of necessity raises concerns about being cut or (or at least greatly inconvenienced) from farm fields, family, adjacent communities for services, etc. Telling a farmer they have to go an extra distance to get equipment or stock on a field because an underpass is too small, or telling someone they have travel 20 extra kilometers to buy a bag of milk, isn't going to garner friends. The area isn't like parts of central or western Ontario that are grids of regular concession and side roads where a diversion is often a couple of kilometers.
Add to that wildlife crossing since the ROW will cut through the Park-to-Park corridor that follows the Frontenac Arch between Algonquin and the Aderondacks.
No doubt a lot of this is solvable. HSR is new to us but not the world.