The
'74-'76 Voyageur II was basically a continuation of the
'73 World Voyageur, with the only differences being price, colors, and the addition of a 25" size.
The bike in question here looks to have an original frame/fork, headset, stem and handlebars, but literally everything else looks to have been changed. The serial number starts with G4, which I believe indicates July '74 frame production.
The World Voyageur/Voyageur II was a very high-end bike in the Schwinn lineup, 2nd only to the Paramount from '73 through '76. It was finally replaced in
'77 by the Volare.
As for the value, there's one on ebay right now that appears all original except for the seat, shifters, and missing brake safety levers:
http://www.ebay.com/itm/Vintage-Road...-/360435723782