Pictures of Rust on '03 Tacoma- Need diagnosis

If it gets bad, yea. But this is not about surface rust, it is about the rust rotting the frame (you can easily put a hammer through it). Normal surface rust isn't that bad.

Also, where the frames get really bad is toward the rear where it splits (forget what it is called... wishbone maybe?).

 

It's not a big deal to an experienced mechanic.
Pop a few bolts off the box, then lift the cab off.
Everything is exposed for easy removal.
New frame is brought in and the parts are reattached. I'd recommend new shocks because labor will be free. Same with a new exhaust. Free labor.
The mechanic will be able to finish the job quicker with the new parts.
Frame, rear springs, brake lines, e-brake cable, lower control arms, hardware......
You'll get new brake fluid, antifreeze and an A/C recharge because that will have to be disconnected.

Mine frame was replaced in 4 days and I was the first for the shop.
Parts being replaced are common. They all do shocks, mufflers, clutch jobs, etc. all the time. These are done in better working conditions.
Need a clutch? Do it now as labor will be cheaper.

My truck runs and feels like new without a new truck payment needed.

 

My exact worry. Some dealers will do it fine but I'm sure there are some that will botch it up. I hope it get's straightend out for you

 

The electrical problems took some time to show up. The blinkers flash the clock and radio. The emergency lights flash with the blinkers weird stuff.