Continuing from what robbymcc said.
You need to progress Jessica’s story to get her to sell the manor.
Don’t worry about levels and stuff, that’s act 3 content.
And it seems the rest of your problems are that you either don’t have the main story leads or you’re not following them.
If you don’t have them, you missed a step in the sequence.
Visiting Gramps
First, check if he’s still in the garden. Then go to the map and take a train to the mountains. Talk to him.
Training
Gramps won’t spill the beans until you’re ready. So do the 4 levels of training. Then talk to him again.
Someone shot the messenger
Gramps still won’t talk, he needs you to fetch a pigeon on the lake. It’s on the map, you have to check it at least 3 times. Bring him the pigeon back once you found it. A bit more talking and now you should have the main story leads.