On a trip to Seattle, we were looking for a quiet seaside village to spend a few days with our young family. This place was perfect for that. We had a 1 bedroom suite with a pull out couch that worked well for our 3 and 4 year olds. It was very spacious and the kitchen has nearly everything you have at home. We didn't have to drive anywhere once we got there as the beach is right across the street and many restaurants nearby.
If I had to be picky and mention some downsides, I'd say the pool was a bit dirty with pine needles in the water and hot tub, stained cement, and stained carpets in the hallways. Not a huge deal for me, but I wonder why the hotel wouldn't put more effort there.
There is a nice grocery story 5 miles out of Birch Bay near the I-5 as you come in, along with a Woods Coffee, Jack in the Box, and Bob's Burgers.
It wasn't easy to book online through the Raintree website as we couldn't select our province of residence, so we went through bookings.com. We didn't really interact much with the staff but they seemed nice when we did.
Overall, the Sandcastle met our expectations and we would recommend it as a good hotel in a great location.