You''ve chosen some awesome destinations, but as an American I can offer my favorite stops in these areas, and maybe save you wasted time and money. Las Vegas: stay at the Luxor- $85 weeknights, luxury on the strip, specify a pyramid room high up, close to all the attractions and monorail.
Hawaii- skip Honolulu and Waikiki, head direct to Maui, rent a car, best value hotels in Kihei. Drive to Hana, bike down Haleakala. Maui Tropical Plantation.
Los Angeles- Hotels near airport or disneyland, rent a car!!, don't miss-Disney, Universal, Hollywood, Santa Monica, Farmer's Market in Hollywood, San Diego if you have time.
Bon Voyage