You would be good to go as long as the streets are not closed off and alcohol is sold and/or consumed in the festival area. Memorize the following law, it will be your OC bible if you do not have a CPL. Remember, each place listed below includes the parking lots.
750.234d Possession of firearm on certain premises prohibited; applicability; violation as misdemeanor; penalty.
Sec. 234d.
(1) Except as provided in subsection (2), a person shall not possess a firearm on the premises of any of the following:
(a) A depository financial institution or a subsidiary or affiliate of a depository financial institution.
(b) A church or other house of religious worship.
(c) A court.
(d) A theatre.
(e) A sports arena.
(f) A day care center.
(g) A hospital.
(h) An establishment licensed under the Michigan liquor control act, Act No. 8 of the Public Acts of the Extra Session of 1933, being sections 436.1 to 436.58 of the Michigan Compiled Laws.