You are on the right track in knowing the feed store is the best place to purchase seed A mix that could work in your area is Forage cowpeas or Iron/Clay peas at 40lbs per acre, with Alyce clover at 10lbs per acre and possibly American Jointvetch at 5lbs per acre. And all of those will need the inoculate you mentioned. It can be purchased at the same place you find these seeds most likely. Inoculate is needed for legumes to acheive their fullest, its a beneficial bacteria needed for proper root developement, among other things. The soil temperature should be in the upper 60s before planting the seeds mentioned. Soil test would be good also, if your soil is very acidic, it could hinder some of the legumes. Good luck!!