What type of dog do you have? We trained our Pomeranian in 2 days to litter box train. She never leaves the home... goes straight to her litter box, just like a cat. She was 8 weeks old when she trained in 2 days. She's 2.5 yrs old now. She sniffs her litter to make sure that's her stuff (
), then she jumps in. Just make sure your dog has his/her 'stuff' in the area you walk him/her.
Good luck.