No idea about

The goldenbustours offers lots of tours of the west coast of america for travelers. I also want to take one tour of west coast region through this site, but no idea how many days tour is best for me for exploring the west coast. Would you like to help me in this regard?

it depends on your budget and mode. The goldenbustours agency offers diverse tour from 1-day trip to 12-day trip. SO it's upon you that how many days you want to spend while this journey. So let us know how many day's trips you want to select? After that, I will recommend you the trip according to your desire.

I will go for day trip from washington dc.

west coast is a most beautiful region for travelling which offers a lot of most fabulous and luxury places to enjoy some time there like:

Yosemite National Park
Golden Gate Bridge
Yosemite Valley
Half Dome
Golden Gate Park
Disneyland Mount Rainier
I hope my shared information would be useful for you.