A stock vechicle can make it up Bald. Maybe not the same line we take, but Bald has many lines and routes to get to the top. As I remmber Brewer isn't all that bad either. My Brother-in-law made it with his ford ranger, the only mod was 30" tires and a factory LS. I was with 31's, 3.07 open and 3" Rough Country lift. I was practiaclly stock myself.
I thought I had a picture, but I guess Brewer wasn't that picture worthy. Anyway a stock XJ can make it, jst make sure you bring the ecentials listed on our Bylaws off the main page.
Legally required automobile insurance and registration;
Fire extinguisher;
First Aid Kit;
Tow Rope (no metal hooks allowed), Tow Chain, or Winch;
Safety belts;
Spare tire, jack, and lug wrench;
Hooks both front and rear (or suitable attaching point)
CB (HIGHLY recommended, but not mandatory)
You have this, you'll be fine.