in that case look up in cabelas or bass pro for one of those square two sided grilling racks. The kind yyou open up place the food between the two grates and then cook over the fire. They work great with small game and fish
Heres a link,.
http://www.yardandpool.com/Non-Stick...ket-p1695.html
It may not be as rustic as using a green stick as a spit, but they make it easy to cook them to perfection.