Is the sculpture park walking distance from the Seattle Art Museum?

Depends on if you like to walk. We do and it is an easy walk, passing by Pike Place Market along the way. If you decide not to walk, and have your own car, there is a parking garage under the park.

or if it is a weekday you can jump on the bus on 1st ave- I believe it is a ride free zone, and just get off before Broad St

Doable, but not really close.

According to maps.google.com it is one mile from the Seattle Art Museum to the Olympic Sculpture Park.

The most interesting way to go would be to walk down Union Street to the waterfront (Alaskan Way). Walk along Alaskan Way going north (to your right).

On a clear day you will have a great view of the Olympic Mountains.

Yes it's doable. It's, what, about 15-16 blocks? Alaskan Way, Elliott Ave or Western Ave will get you there from the Pike Place Market area. Go to http://www.seattleartmuseum.org/visit/OSP/ and click the maps links.