I'm sure that this has been posted before, but I'm going to ask anyway because of the nuances (I believe) of my problem. I've got a 60+ year old home that does not have a house trap at all. This morning we noticed that sewage was leaking up from the 2 drains (one in the garage) one in the basement, and called roto rooter. He opened the drains and informed me that there are several (unknown how many at this time) root masses blocking the sewer pipes and while we could cut the roots out and cut down the tree, the roots would likely continue growing and we'd eventually buckle? the lines and have to replace them completely. He suggested putting in a new line outside and running it to the street (probably 30 feet) and bypassing the current lines. He quoted me nearly $9000 which is almost 10% of what I paid for the house.

Should I:
1. Go ahead and do this--there's no alternative (but shop around on price).
2. Try and have the roots dug out and then put root killer down the sewage pipes 1x per year.
3. Cut down the tree and do #3.
4. Call the previous owner and threaten to sue until they help fix the issue. This isn't a new issue, it's been growing this way for years (so the plumber says), and we would be required to disclose it to new owners--it wasn't disclosed to us (our inspector didn't run a camera through the plumbing).
5. None of the above--let the place fall over, chances are it's worth less than we paid for it anyway.