i think djbill would eb correct on it being 76-78 with the freewheel in the sprocket.
i know a few suburbans form that era had that setup as well as some of the varsity's
it's tough to determine a price on it without pictures but i know i have seen Schwinn road bikes going for anywhere from 100 up to 1200 bucks for the paramount so there's a wide variety there.
if it is in fact a suburban,then if in good shape you could get about 200 for it. some people like the comfort of the suburbans.
varsity are anywhere form 75 up to 300 depending on condition.
i just sold a tall framed varsity that needed a lot of work for 110 bucks.but it was ride able just needed work.
condition is everything on these form what i gather it seems the slightest scratch will drop the value drastically. but that might just be the pickiness of people.
hope that helps a bit.
my advice would be compare them on ebay to see what their fetching on there and maybe deduct about 20 percent of the prices and you should have a fairly decent opinion of value on it.