Broad day light you'd be fine. Don't go there after dark though. My DM lived across the street from the park near the Elementary school there. We would hear gunshots all the time.
Once there was a fire fight on the south side of the park. Their were so many shots we all figured it was firecrackers, nope. When we left 45 minutes later, half the manch pd was there investigating.

No place in Manchester is that bad, in my experience, but the worst areas IMO are

New Horizons on Manchester and Pine.

Walsh Ave. on the west side.

Stanton Park.