I just bought a 98 Legacy L with 190k on it... ran great for 2 days and literally just shut off mid drive with no luck on restart. Replaced the battery, cam shafts sensor, and fuel pump with no luck. Hoping it's not the fuel pump relay. My computer port isn't even reading so now I am flying blind. If it's the relay, is my only option to rip out the dash? It's visible but inaccessible from underneath... any advice would be huge!

You need to listen for the fuel pump running for 1-2 sec when you turn the key to on.  You may have to have someone else in the back of your car to hear it although it can be heard clearly from the driver seat if you listen carefully.  Failure of the fuel pump is very common.

Does the engine crank when you turn the key? Or does it not do anything at all?

 

When you plug in the code reader does it power up when it's plugged in, but just won't connect with the ECU?

One way to test the fuel pump is to pull the fuel line at the fuel filter. Messy but effective.  Wonder why no one has mentioned a broken timing belt?