I've got a couple of photos taken in that park last September but I don't know how green it is now. I can't figure out how to actually post the image from SmugMug so am posting the link to the gallery I stuck them in.
http://davidhobson.smugmug.com/gallery/1831702
As you can see there is a pavilion and a bridge, besides a train on the other side of the park. I'm not sure how close you can actually get to the train... could be a cool bridal shot. Since your bride lives in Plano I'll bet she knows exactly where this is - it's just west of downtown Plano.
Hope this helps.
Stephanie