We lived in NL for over 11 years and made at least 20 crossings with our dog with never an "accident" or problem. We recommend that you leave the dog in the Tundra where it will feel at home. To avoid any anxiety we gave him a relief break before reaching the terminal each way. In North Sydney there are grassy areas near the lights
by the "Lick-a-Chick" and the NL Visitor Centre outside Port-aux-Basques is great when leaving NL. Our little guy never had a problem with the voyage time. Your decision will depend on the severity of the anxiety problem. The kennel stowage area is clean and you can visit your dog there but there are usually several "barker/howler's" there that can be set off by visitors and we felt that that was more stressful than the car. ..........Your call. It's beautiful there and it would be a shame to miss it. Good Travelling!