I visited Blossom Music Center for their Fourth of July festival featuring The Cleveland Orchestra and it was magnificent! Although the center is about an hours drive outside of Cleveland and a little hard to find (even with Google Maps; I'd definitely recommend looking it up ahead of time), it is a perfect spot for a picnic and night enjoying music and nature. You can bring in all your own foods, and I highly recommend it! Alcohol is also permitted as are blankets, baskets and the like. If you have a parking lot option, I must recommend Lot A, you may have to pay extra but it's highly worth it.
We ended up purchasing tickets underneath the pavilion, it's definitely a splurge ($$$) but is a fantastic way to enjoy the show. The sound is spectacular (although if there's a nest of baby birds it might drive you a little crazy with all the cheeping). However, I have never been so happy to enjoy Gershwin and Tchaikovsky followed by cannon fire and fireworks to celebrate a fourth of July weekend. Pro Tip: get out ASAP, there's a lot of traffic post-show!