Welcome to the forum, snikh ~
There are lots of ideas already in place on the Canadian Rockies Forum, the more senior forum to this one. Click on the blue print link just above your avatar to go there.
Once there, look in the Top Questions to the upper right. In that section, you will find the question "what itineraries?" which is a link to Trip Reports left by other visitors. Also in the TQs, you will find an article about which route to choose to drive from Calgary to Vancouver.
Another very valuable activity is to read other questions being asked and replies being given, again on the more senior CR Forum. Doing this is an invaluable way to pick up planning, itinerary and route information. Read on to p. 2, 3, 4, ..... as needed.
A very useful tool for generating driving routes, distances and times is:
Because your journey will take place 90% in BC, you might also find helpful information on the BC online Tourism website:
With 19 nights, you will be able to sort a very nice vacation. You could even take a couple of days for a portion of Vancouver Island if that appealed to you, or you could wend your way through some pretty attractive locations in BC to make a week of it to get to the coast.
July 1 is Canada Day here and a busy long weekend everywhere. Reservations would be needed in advance for accommodations for that weekend.