In my opinion, you don't need a car unless you're possibly looking for example an out of the way restaurant or if you're heading to Whistler ski area (& summer resort) or Victoria (capital of BC) by ferry.
Then again you can also take a chartered bus or take public transit for Whistler and Victoria.
Most attractions are accessible by public transportation system - buses, subway and elevated tram and SeaBus, chartered tourist buses, or the 'hop-on hop-off' tourist buses.
The tram system consists of 3 lines; not like The Tube in London!
Check here for additional tourist attractions and ideas.
The SeaBus goes between North Vancouver and Vancouve and is a short 10-15 minute ride. From the SeaBus terminal in North Vancouver you can transfer to the local transit bus to take you to the Capilano Suspension Bridge and Grouse Mountain (ski area and other on mountain activities).
If you're physically inclined you can do the Grouse Grind - walk up to the top of the mountain from the parking lot - no charge! There will be a fee to take the gondola down.
Great views of Vancouver from the top of Grouse Mountain when there are no clouds.
Both pay attractions are close by to each other and not more than 10 kilometres away from the SeaBus terminal.
Lynn Valley suspension bridge is free (North Vancouver)
Check here for transportation fares and info.
Since Vancouver is next to the Pacific Ocean - there are quite a few seafood restaurants. You can order fresh wild salmon, oysters, halibut etc. Too many choices.
Vancouver is a multi-cultural so is your choice of food options.
August weather should still be sunny and warm. Still, there might be a chance of rain; Vancouverites don't tan they rust! Bring an umbrella and a light rain jacket.
If you're arriving at YVR Vancouver Airport you can take the Canada Line (subway and elevated tram transit) to downtown Vancouver in 25 minutes for $8.75 per person. Note: Cheaper on return trip to YVR.
YVR website says it will cost between $34-$36 for cab fare downtown. Putting it another way if 5 or more people its cheaper by taxi.
If you need more specific info, please make another post.