Hey Sar,
Haynes probably has a manual but my guess is that it's lumped together with other models and they call it the W-body manual. They are probably not up to 2000's yet either. They usually lag behind a couple of years.
Helm's is definitely the way to go if your serious about repairing your vehicle. If it's anything tougher than a brake job or changing the water pump, the aftermarket manuals usually tell you to take it to a certified mechanic anyways.
If the price is scaring you away, keep an eye on e-bay. I got mine for less than $40.00. That was a steal though.
Most of the time it's closer to $75 or $90.