Hello Charliechix
Welcome to TAS
First thing to consider is that goats are a HUGE commitment. Even if you aren't milking, you will still need to be on hand for twice daily feeding, ensuring they have fresh water (they drink quite a lot!) aware that if they are going to get ill it will be at the most inconvenient time possible (ie. xmas day, 3am, when there is a blizzard...)
There are a great many things that are toxic to goats (certain trees and plants) so you need to make sure the land is free of them.
Personally Id' say the best option at this point is to find a local goat club or keeper who will be more than happy to show you their set up, let your sister have some hands on with them and get a feel for if she still wants goats.
I have 4 goats currently, I'm milking 1 I have a kid suckling off of his mum and then a castrated male. Its hard work! Even going on holiday takes a lot of planning now, making sure they are in tip top condition, that I have a relief milker, enough feed, hay and so on.
LIsa