TJ Sahara

I just recently purchased this jeep after having another 2004 Sahara that I was absolutely in love with that unfortunately was totaled. This jeep has significant rust and I'm just wondering if anybody can advise me on the costs/what needs to be done to the frame. I can handle the body rust myself, but the underneath is what I'm concerned about. I'm really looking to save it because although he's an old guy, I love this model and plan to get the engine replaced in the future (it's currently at 130,000 miles so that'll come based upon need). Thank you!