As far as the EBCM goes, you can get it refurbished through eBay rather than buying a new one. Mine was throwing a slew of codes randomly. I got it repaired for $100 and it's worked like new ever since.

If the brake lines are leaking or rusted through you'll definitely want to get them replaced. You don't want to try stopping in a massive Hummer and have your brake pedal turn to mush, it is a very scary situation

 

I haven't looked at the brake lines on the h2 yet, but most cars they're pre-bent hard lines, and nothing short of a nightmare to install, and expensive. I wish they'd come up with a viable solution for soft lines but i haven't seen it yet. They're exposed to the elements, especially if you far enough north to get snow and salt. They rust out and if they burst, it's not pretty. I always get the underside of my cars/trucks washed in the spring to clear all that salt out, otherwise it just eats away at stuff.