Issaquah has a really cute old town with lots of restaurants and shops
If you're staying in Seattle or West Seattle you must check out Alki Beach! It's "Little Miami" and a fun place to grab a bite, take a walk or just put your toes in the sand.
South Lake Union is a great place to take a short cruise and see the sites. You can often find brunch, happy hour or dinner cruises that take you around SLU and Lake Washington. In the summer it's a great place for paddle boarding or taking a spin on the Electric Boats!
The Smith Tower Observation Deck is amazing! A beautiful 360 degree view of Seattle!
Downtown Bellevue is a really great mini city located between Seattle and Issaquah. There is great shopping, dining and hotels.
Snoqualmie Falls is a 268-foot waterfall- one of Washington's most popular scenic attractions and is known internationally for its appearance in the cult television series Twin Peaks. There is also a great restaurant overlooking the Falls-Salish Lodge and Spa.