Kid friendly? Absolutely! There will be people assigned to watching for kids near the river as well as near the fire pit area. (river is not raging, small, slow, shallow area of river with very small "deep" area about 6 feet deep near center, banks about 3 feet deep) sandy banks
How to have a good day? Comfy shoes! A blanket or sweater. Note, location is by water, so maybe a towel, some lake stepping-in shoes, extra cloths if you'd brave the September cold water. Bug spray!
Food? We are planning for a chicken and a beef main dish, but we've decided to be young an in love and proceed with the wedding regardless of funds, last minute pizza may be announced the month of. Vinnies of course in the event it is pizza.