You have several options to stay on the mainland side of the Strait. Earlier this summer we went from Pender Harbour to Secret Cove to Gibsons. Keep in mind this is all in the Strait of Georgia and potentially bad weather. In early July we had 25-30 knots of wind on the nose. When the current ran against the wind the seas were up to the top of the pilothouse on the 22...not pleasant and we weren't going anywhere fast.
Once you get to Howe Sound you have lots of options. Gibsons, Vancouver, Snug Cove, and many other marinas and provincial parks. We went all the way in to Squamish so we could get up to Whistler for skiing on the glacier and mountain biking. The further in towards Squamish we got, the prettier the scenery was.
From Howe Sound we crossed the Strait and spent a night at Wallace Island before returning to Anacortes via Roche Harbor. Like Bob said, arrive at the customs docks during business hours if possible. Clearing into the US was straightforward...the officer scanned our passports, asked us a few questions, entered some information in a computer, and we were on our way. No more than 10 minutes. I assume Blaine will be the same but have no first hand experience.
If the wind is calm the trip down the Strait will be quick and easy, but watch out if the wind is forecast to pick up. There aren't a lot of places to seek shelter between Jervis Inlet and Howe Sound.