Between 1 and 2pm at MSP there are flight arrivals from AMS, NRT, and CDG, so it's a busy time of day. But MSP immigration and customs are usually pretty fast and efficient. My instinct says a 95 minute connection at MSP is safer than 2 hours at JFK.

You will enter into concourse G after you clear security from customs. Immediately to your right there will be screens with flight listings to check your gate. There's no way to know this far in advance which concourse the Boston flight will use. I looked it up and found that today it was D concourse, a 5-10 minute walk from where you will enter the terminal, while yesterday it was a lower G gate, about one minute from where you'll enter.

Just to explain MSP a bit: MSP has two terminals, Terminal 1 (Lindbergh) and Terminal 2 (Humphrey); Delta uses only Terminal 1. Terminal 1 has seven concourses. Delta uses all of them, so flights can be quite spread out. The longest concourses have moving sidewalks and the very longest, C, has a tram. There are lots of electric carts that you can flag down.