We have a 1/4 size practice field in Saginaw with 5 of the 9 defenses built (still working on the others) that you’re welcome to come and use.
Alternatively, our parent organization, FIRST of the Great Lakes Bay Region, has a 90% field with basically all field elements (including some made to the metal, competition spec) in their facility in Midland (it’s also home to teams 2619, 5509, and 5424).
EDIT: Cam beat me too it.
You’re welcome to come to either of these locations any time we’re there, we just ask you let us know ahead of time.
Also, though I can’t speak to their policy on guests (though I assume they’re open to having you come as well), Kettering University in Flint has a full size, competition spec playing field (though it’s possible some/most of the game-specific elements are the wooden team versions). That said, I suspect they will also be VERY busy next weekend as a LOT of teams use that facility.
Thank you to teams 2619, 5424, and 5509 at the FIRST of the Great Lakes Bay Region for allowing us to utilize your field this past Saturday. It was a tremendous help for us to practice and learn quite a bit. We hope one day we too can return a favor like this to you. Or, at least be able to mimic your willingness to help others as FIRST inspires us to do.