I think two things would help -
formal casting lessons
There are many good instructors in MA, for instance Bill and Sheila Hassan @ 617-759-8627 who are located in Medway, MA. In fact if you look on the FFF site the certified instructors (including myself) are listed.
applied time on stream and pond
From what I know of trout fishing in Oregon, there is some stellar stillwater trout fishing with huge trout. Wyoming and Idaho will call for more stream work. So you'd be best to try both.
I would suggest fishing White Pond and Walden Pond in Concord, or one of the phenomenal kettle ponds on Cape Cod. If you have a float tube you'll be in good shape, or borrow one from a friend.
For stream fishing, I would visit the Deerfield and Swift, also the Westfield and other rivers to the west to get the most realistic taste of trout fishing out west without actually being there. If you have a NH license, there are even more choices including the Pemi, Swift, Sugar, Ammonusuc (sp?), Contoocook, just to name a few.
I would not delay too long or the conditions will become unrealistic - trout are early season and late season fare in MA. Kibbies might give you a false sense of accomplishment in July
If you want your trip to be experienced further up the learning curve I would take these steps.