Hello , my name is Joe.
If the vehicle will roll , then that usually means that the park brake shoes have been worn away again.
An estimate of $2000.00 sounds like they may be including a new park brake hydraulic pump assembly in the estimate. Most often, the root cause of your issue is leaking and/or defective fluid pressure switches.
Typically, when the pressure switches go bad, the electro-hydraulic pump will not be able to keep the park brake released, then the park brake shoes will contact the park brake drum in travel. When the park brake shoes contact the drum in travel, then they will burn away until they will no longer be able to hold the vehicle from rolling.
If the park brake does not hold the coach , then the brake shoes may have been severely worn or damaged from dragging on the drum while in travel.
The park brake shoes are located inside the drum on the transmission tailshaft.
In most cases , the park brake drum will need to be removed , and the shoes inspected for damage. The park brake cable will need to be adjusted as well.
If the shoes are worn away or the drum shows signs of heat damage , then it is likely there is a fluid leak in the auto park brake system that must be repaired as well.
So, you might get away with replacing a few pressure switches, refilling the fluid reservoir, and another brake shoe replacement. But the technician may determine the pump unit is defective, and this part will add about $1300 to the repair cost.
I have heard of manual park brake lever kits and have seen them on the internet, but do not have any personal experience installing them.