Are you looking for an actual bus tour or a TA that can set up a trip for you?
Either way, you are very late in planning this and finding accommodation will be hard.
you need to post this on the Vancouver forum as that is where you are looking for a travel agent
This is more of a self plan forum so do not expect much +you need to say want kind of tour you are looking for and what age group as it does make a difference.
do you want a fast paced, look and see, which some are offering or, do you want a bit slower and be able to spend time in the towns along the way instead of get off the bus take a few selfies and get back on to the next stop. or are you a young backpacker that is too young to rent a car.
Look at Collette coach tours and Trafalgar coach tours. Mid-range affordability. Less expensive are KeyWest and Caravan.
You could also look at Moose Network.
the above are not travel agencies but bus tours which you can book via a travel agent most of the agencies in Vancouver will have those on their list.