Well, I'll give Easy Come, Easy Go this - it's not as unwatchable as Harum Scarum.
Watching Elvis films is a bittersweet experience. I love seeing him - he had such an incredible voice, presence, and energy, but what a waste as far as his films. Had he not been tied to Colonel Parker, film-wise, he could have done some interesting roles.
I'd say let's not dwell on the past, but unfortunately, with Elvis, it's all we've got. "Easy Come, Easy Go" was one of his last films, and it was made during the hippie movement, so Elvis has to deal with a lot of free spirits. He's after some underwater salvage, and he has competition. There's the story right there.
There is a yoga class headed by Elsa Lanchester who sings a little song - I guess at this point, they threw everything but the kitchen sink into these films to make them bearable. Frank McHugh turns in the best performance of the film. He's wonderful and very funny in what would be his last film. Elvis is charming, of course, although by 1967, doing these films was a painful and angry-making experience for him. The songs are terrible - my understanding is that Colonel Parker figured out by the mid-60s that the lower the budget, the more money he made, so apparently, there were no songs written expressly for the movie.
Elvis could have been in "Midnight Cowboy" or the Streisand remake of "A Star is Born" but the Colonel was afraid of losing control of him, and Elvis was afraid to leave. Colonel Parker was his lucky charm. Colonel Parker had given him all his success. Colonel Parker was taking 50% of everything Elvis made. Colonel Parker made Elvis a slave to the Hilton Hotel because he kept telling the management to take his gambling debts out of Elvis' deal. Colonel Parker wouldn't look at Elvis' dead body, but took Vernon aside and made him sign a document that the court later negated since it was detrimental to Lisa Marie's inheritance. Yes, Colonel Parker was a prince. This movie is just one example of everything he did for Elvis.