Can anyone tell me is their any way to save peoples in east Rivermont?
After arriving there, the first morning you can go out and do stuff:
Night one: Save the kid, grab the hammer off the corpse, check the big house to see what happened to the merchant's daughter and raise the bridge. Don't forget to read Sir... forgot his name's journal before leaving the room you got the key in and -- in true RPG fashion -- take everything that isn't nailed down no matter how nonsensical (Mouldy chicken, mushy carrots etc.). It'll make sense later.
Night two: The actual infiltration. The reason you want to get all the sidequests done on Night One is because if you cannot pass the stat requirements to talk to Tubbers, you'll need to go through the well and you need a full energy bar for that.
Do that, and both your mother and Marie are saved. Get a day late, you can save your mother but Marie's gone. Two days and you can save neither, three days is game over. So if you want to maximize how many you save, you need to get it done in two nights.