Visiting Six Flags New England! 

That's awesome! Saturdays in July and August are definitely very busy. I have found that "rope dropping" (arriving just before the park is scheduled to open) will allow you to get in at least one or two of the most popular rides before it gets too crazy. I will also say that usually the Hurricane Harbor (water park) area is the most crowded so that's where you'll really see long lines consistently through out the day. The lines on the "dry" side of the park are typically much more reasonable until Hurricane Harbor closes at around 6pm. After 6, some Hurricane harbor folks will leave but many will stay for the last few hours and lines on the dry side will stay pretty long. For the dry side, the Super Man roller coaster usually has the longest line by far so getting that done early is a good idea if you want to do it. Hope you have a great time!