Buy a 10ft roll of 25h and a couple masterlinks or buy a chainbreaker tool.....The roll of chain and masterlinks will cost ya the same practically as one thats already made for the bike.If you want the direct replacement chain count the links because theres 5-6 different chain sizes........
An old saltflats bike runner trick,,,,take the rusted chain and put it in a bottle of cocacola for a few days,,wire brush it and then oil it but from what your describing its shotter than shot..............Good Luck
An old saltflats bike runner trick,,,,take the rusted chain and put it in a bottle of cocacola for a few days,,wire brush it and then oil it but from what your describing its shotter than shot..............Good Luck