Greetings and welcome to Vancouver... or welcome soon..
I hope I can answer some of your questions.
The BW Chateau Granville is on Gravile street, a few blocks down from the Main downtown shopping mall (The Pacific Center) and the main shopping street (Robson). The hotels you are staying in is fairly central. Right on the bus line and only a few blocks to the skytrain station (at Pacific Center). At night there are quite a few bars in that area, thus some caution and common sense need to be taken, but generally there should not be any problems.
As for renting a car, that really depends on where you plan on going, but with a combination of Bus, Taxis and Skytrain you can get everywhere quite easily.
As for places to see here are my thoughts:
1) Stanley Park. It is a nice casual walk of about 1 mile from the entrance of Stanley Park to the Cruise Terminal.
2) Pacific Center (Shopping downtown)
3) Robson Street (Shopping and people watching)
4) University of British Colubia Museum of Anthropology: Huge museum, everhting and anything regarding the people of the areas and most areas around the world.
5) English Bay. Beach area with gret sunsets and views. About a 30-45 minute walk along the beach area from your Hotel.
I can probably think of more and if you have any specifics please let me know, as I live in Downtown Vancouver and would be more than happy to give whatever info / advice I can...
