There's an '85 Schwinn Super Le Tour for $200 in ready-to-ride shape in my size on CL here. Looks good, too. Definitely room for larger tires and fenders, and should check all the Eroica boxes (friction shifted Suntour Symmtric units). There's also a my-size Trek 500 in RTR shape (beautiful paint, still) for $275. So I think it's totally doable for a thrifty sum, bike-wise. No delusions of Concours grandeur need apply, but hey, we're here for the fun.