I've stayed at most of your campgrounds listed on the itinerary. I would take your toad. As suggested , there are a lot of narrow winding roads in some of the communities you will be visiting. My hometown of St. Anthony is also on your list. It is getting a bit late for icebergs, but you may be lucky. Whales for sure. My buddy owns a restuarant that I'm sure you will be visiting. It's called "Lightkeepers Cafe and Leifsburder" at fishing point in St. Anthony. Lots of seafood on the menu. Mention my name and he'll probably hike the price.
. You shouldn't have any problem with gas stations. There is only one Costco Store in Newfoundland. St. John's and they usually sell gas for6-8 cents a litre cheaper. Sometimes, not worth the wait and it's not really big rig friendly. Mosquitos and black flies abound at Triple Falls CG. Be prepared. A light jacket and long legged pants are a must for the evenings and most days too.
When you stay in lunenburg, give me a call. I live about 20 minutes away in Bridgewater. Feel free to ask any questions. More than 'appy to oblige.