I am not good with valuations, however, your Sports Tourer is in perfect condition right down to the Hunt Wilde bar tape. All original, all clean and like the day it left the Schwinn dealership. I'm with
bikemike73 $400. I think he might like Sports Tourers. I do too, however, I don't own one (yet).
If you don't want to sell it, don't let your neighbor pressure you into it.