It's possible that the grease has dried out in the hubs and/or headset and will need to be repacked. But all of these bearings are probably sealed (but not sealed-cartridge) on a bike like the 1500, and I suspect they're smooth enough. Rusty chain might be a problem. Whatever the case, you'll probably want to remove the chain and soak it in solvent, let it dry, reinstall and use whatever chain lube on it. Other than that, just clean off dirt, dust and grease and you're likely good to go.