I'm going away for 3 weeks and she's unlikely to eat when I'm not there plus which it'll be much easier for the people keeping her if she doesn't have to be fed.
Would there be any problems in letting her have 3 rats in 7 days and then nothing for 3 weeks?
While I realise this is massively departing from the feeding guidelines that most of us follow, in the wild there would be no such guidelines and as far as I know as long as the snake takes the food then there's no danger? I definitely wouldn't be assisting or anything, I would just be doing normal feeds.
Even if it was possible it wouldn't be in the snakes best interest to be digesting for such a long period of time, its massively energy consuming. They can go months and months without food so three weeks without would probably not even be a blip to it.
When ever im on holiday i have a friend that comes to my house every 2 days to change the water and change the paper if required. All of mine are just left and i offer food when i come back, it will not harm them one bit in the difference.