Okay, so you're kinda all over the map. Are you like going to fly on this vacation? If not flying, where pray tell are you starting? I'm assuming the greater LA area?
I'll toss out some ideas - you use google and tripadvisor.com to determine applicability.
Key West, Florida
Myrtle Beach, South Carolina
Panama Beach, Florida
Pensacola Beach, Florida
Virginia Beach, Virginia
Williamsburg, Virginia
Washington DC
Newport, RI
Cape Cod, Nantucket, Martha's Vineyard
Boston, including Salem, MA (best in the fall, late Sept/October)
Kennebunkport, Maine (southern Maine really - includes Kittery, York Beach, Ogunquit and Portland)
New York City - shopping and theaters if nothing else.
Ocean City, MD
Cape May, NJ
Niagara Falls (best to go to Canadian side)
Quebec City, Canada (poor mans European vacation, primary language is French but they all understand and speak English)
Montreal Canada - loads of fun stuff there. Cirque Du Soleil is a Montreal thing, also French speaking and very Europeanish
Lake George, NY or Lake Placid, NY - the Adirondack's are America's best kept secret.
San Antonio, TX (River walk, Alamo)
New Orleans, LA
Estes Park Colorado
Jackson WY
Yellowstone National Park
Glacier National Park (Montana)
Seattle (underground tour, Pikes Place Market)
Vancouver Canada (most beautiful city in the world - my opinion)
Olympic National Park, in particular the Hoh National Rainforest http://www.nps.gov/olym/planyourvisit/visiting-the-hoh.htm
San Francisco - favorite city in America
Santa Cruz, CA - beach with stuff and shopping - Mountain biking started here.
Monterey, CA + Carmel, CA and Big Sur
Lake Tahoe, CA/NV
San Diego, CA
FYI - the best US mainland beaches are on the east coast, with eastern Florida (gulf side) being the best of the best. If you want a beautiful beach go to Sanibel Island Florida.