'96 Tracker 2dr 4wd 5spd, 100k mi., runs good and is now a box-stock DD. 

The problem is that 10 years of Chicago winters and 8 in Ohio have not been good to it.  It looks OK from the top, but underneath it is one big ball of rust.  The brake and fuel lines and fittings are not leaking, but are badly corroded.  The tubes holding the tank shield are almost gone.  The rockers are almost gone.  There are holes in the body behind the rear wheels big enough to stick your fist through.   The frame is rusting out where the round crossmembers go through the frame in the rear.  Whenever I try to turn a bolt, it breaks off. 

I am a pretty decent mechanic, but I am not a welder or fabricator.  I really like the vehicle, but I don't know if it is worth the effort or the expense. 

Would you recommend even trying to save this truck, or should I give up on it?   

Massive rust of the frame and the body panels are the worst.  You can rebuild engines, trannys, transfer cases and differentials... but once heavy rust has set-in, there isn't a lot you can do to stop it or repair it long term without serious body panel replacement and swapping frames.

Have you considered locating another Tracker that has a sound body and frame and just swapping over the drive train and other low mileage parts from your current truck?  It would be a lot of work... but long term, a hell of a lot less work than trying to patch together the body and frame of your present Tracker.  I still occasionally see one for sale with a bad engine.... but the Tracker itself appears to be fairly decent.  When you find one with a bad engine but decent body around the midwest, they typically go for around $600-$1,000.

My '02 Tracker developed some serious rocker panel rust a couple years ago and I decided to just cut them completely out and replace them with some steel rectangular tubing.  BUT, when the day comes where the frame is severely compromised and large wholes develop in the sheet metal and/or fenders... I will reluctantly part with my beloved Tracker. 

You can only slow it down once it has gained a foot hold on your vehicle without some serious investment in body repair.  You have to weigh what it is worth to you and how long you intend to keep it.  I don't intend to spend big bucks on body work.  The body shop wanted almost what my Tracker was worth just to repair the rockers.  I elected to do the tube rockers.  It turned out well enough and they are still in very good shape.

Those in the "Rust Belt" are used to the damage done by salted roads, but out on west coast, we don't get much deep rust (unless used as a beach vehicle).  This link is by one of our members, and he resurected a very rusted out one.  http://www.zukiworld.com/forum/build-diaries-how-to-diy/shop-drawing-suspension-kit-sidekick-%28gen-1-platform%29-1989-1998/15/.

I would just take a vacation out "West" and purchase another Tracker that doesn't have much rust, and take/drive it back home.  There are still some good deals on decent Zuks.

Here in Oklahoma, rust-free Tracker and Kicks with blown engines go for $100 or less.  However, it is a 9-hour drive from Chicago.

When I lived in Germany, I saw a trick that owners of vintage autos utilized to keep rust at bay.  At the end of the summer, my friend would spray a heavy oil meant for farm equipment winter preservation inside the wheelwells and all of the rust prone spots.  I might be too late for your current vehicle, but it might be something to consider in the future.