"Best" is undefinable. I'm not quite sure what you are asking, but based on your comments asking about "must sees" for any state I think is a good idea. I'd go a step further and ask "and why". For example, I'd highly recommend attractions like Minuteman Historical Park, the Old North Bridge and Lexington Green if you are a history buff. Boston if you like a mix of old and new. Cape Cod if you want quintessential New England. What I feel is a better way to go about it is to say "I'm going to visit X state in June. My interests are this, that and the other thing. What do you recommend for those and what else would you do"? It's hard to give advice when you have no idea what the poster might be looking for.