I've found the route I'll take for my daily lunchtime walk. I just came back from it, and it's going to be doable.
Basically, I leave the office (corner of Stanley & StCath) and walk along St-Cath up to McGill College. Turn towards McGIll, walk up the Roddick Gates, and cut across campus until I reach corner of Pine and University. Turn left on Pine and walk all the way up to McIntyre Medical (Peel & Pine), then it's straight down Peel all the way to Maisonneuve, and then back to the office.
It's about equal amounts of flat, uphill and downhill. Enough to degrease the old system anyway :)
Wish me luck! (and thanks for all your support)