The duration of trip will take is very much up in the air for a couple of distinct reasons. The first is the fact that who will go on this trip is still an open question. Obviously, I will be going. However, whether Margo and Chris will be along has significant ramifications. First of all, I think that if I am by my lonesome, I will be making better time for the simple reason that I am younger, bigger (an advantage on the longer haul, but not going downhill! Margo and Chris often passed me on long downhills. See below, I'm in the one in orange) and possibly fitter than they are.
This gives me an "unfair" advantage. We would also be camping which would mean carrying more stuff per person than if I went alone and credit card toured (i.e. stayed in motels and hostels), again meaning a slower pace. Furthermore, if Chris and Margo were along for the ride, we would more likely spend extra time in Québec City than if I were by myself. I have been there many times and don't feel any particular need to sightsee. However, Chris has never, to my knowledge, been there and it would be a seriously missed opportunity if he didn't spend at least a day visiting the place, especially as I would a good person to be his guide as I have two degrees in history.
The other complicating factor is work. The initial estimated distance from Montreal to Deer Lake is approximately 1810 km. If one assumes roughly 100 km per day, this translates into 18 days of cycling, which combined with rest days, ferry crossing, visiting my sister, etc. leads to the idea that one could cram it into 3 weeks vacation time. However, that is a very dense chunk of time with little options for variations. The problem arises from the fact that while I currently enjoy 4 weeks of vacation time per annum, my workplace discourages people from taking their vacations in too large a chunk. They can't actually force us not to take such a long vacation as it is not in the contract, but that point has yet to be tested. Consequently, it remains to be seen if I can weasel the time. I am hoping that I may be able get the longer period by saying I am prepared to coordinate the period with other people's vacations to avoid problems.
This problem may be eased by the fact that my sister has recently left Port-Aux-Basques for Norris Point, in Gros Morne National Park. This locale is roughly 70 km beyond Deer Lake. This in turn means an extra two days of cycling. Strangely enough, the extra required time, makes it easier to demand the full 4 weeks of vacation time in one chunk as there is it would be unreasonable to do the distance in 3 weeks.
However, there is yet another complicating factor in that in the coming year, my union's contract is up for renegotiation and as the local representative, I will be on the negotiating team. I don't know how much time it will take or whether there will be a break for summer vacations or what have you. I do know that I don't know.
One option I have thought of would be break the trip up into two sections. One section, possibly with Margo and Chris, would be from here to about Le Bic. I would then take a bus back to Montreal and at a later date, would take the bus back Le Bic and resume the journey. Depending on how long the gap between legs of the journey, I might even leave my bike with a friend of my brother Philip in Le Bic.
One downside of cycling to Newfoundland compared to Spain, is that window of opportunity is much smaller. I will be likely cycling in high tourist season. I was in Spain in May which seemed to be lowish season. I was also pretty much off the tourist beat, unlike my proposed route through the Maritimes.