Can I just leave the old tank and put another in alternative location?
Hate to cut everything up.
It's your boat - you can do anything you want. Keep in mind that water weighs about 8lbs per gallon as you decide on a location. But there's certainly no reason it can't be done.
I've never used one, but if I was in your shoes, I might do some research on bladder tanks - possibly being able to fit it into the original tank (depending on access, of course).