baadbee

The challenge is that the whales are a quite a bit north of Seattle around the San Juan Islands. You either take a long drive (90+ minutes, not that long) and a shorter sail or a long sail. Since cars are faster the long sail option can leave you with less time near the islands. You should consider the transit time when booking. That high speed catamaran Ferry_Watcher mentioned might help solve the problem, I haven't heard much about it. If your travels give you the option of whale watching out of Victoria BC it is much closer to the whale spotting areas.

This is a perfectly reasonable plan for mid May. The roads are in excellent shape and are most likely going to be bare and dry. You are being careful which is most of the battle. Mountain weather can be very weird and inconsistent so double check the reports before heading out and follow advice. Be willing to adjust your plans on the fly. A snowstorm is not probable, but certainly possible, you don't want to be at altitude when it hits. Even Canadians consider the weather around Calgary a little bizarre at times (it has snowed in August).