How can I make an outdoor wedding reception in Lansing,MI work?

I'm getting married in Lansing, MI in July and seem to have waited too late to book a reasonable reception hall. We wanted a reasonably priced hall that would allow us to bring our own food and I started call around in late January but all the halls that I know of that allow you to bring your own food were already booked on our wedding date (I've tried Knights of Columbus, Eagles Hall, and the Okemos Masonic Center). Since we're only having around 50 guests and the reception will probably only last about 3 or 4 hours some of my family and friends have suggested doing an outdoor reception at a local park with a nice scenery.I was reluctant to do at outdoor reception, particularly at a public park however I seem to be running out of options. Does anyone have any suggests of a nice looking park where I might be able to pull something like this off? Any ideas as to how to make an outdoor wedding reception look nice? We are having out of town guests and a photographer so I really really want my reception to look nice and want everyone to have a good time regardless of where the reception is held.