T7 immigration can be easier than some of the other terminals, especially if you are a US citizen, (it's actually become a preferred entry point for me,) but the non-US wait on a bad day can easily be an hour.

Switching airports in NYC is not something I would do without at least 4-5 hours...and not really advisable at all. If you do go that route, look into getting a chauffered car to make things easier. I use Dial 7, who will meet you inside arrivals and take you in a towncar to the next airport for about $100. In NYC, it's a must.