I think the last time I was on this trail it was when i went bike riding with my dad when I was small child. The trolley trail is about 2 miles long with varied elevations making it a moderately challenging trail. Another feature of this trail is that unlike the trails located by Stony Creek Metro Parks Nature Center, this trail allows dogs to travel on it. Just remember to have your doggo on his or her leash should you bring them as they need to be leashed at all times.
As far as mosquitoes go, this area of the park was not as bad as although it would be a good idea to wear bug spray to not only repel mosquitoes but also to prevent tics from biting you as well.
For more information on the trolley trail and Stony Creek Metro Park please check out the following link: https://www.alltrails.com/trail/us/michigan/trolley-trails