A denial on the first home plan puts you at the back of the line, and the honest answer is that the process can take months from that point.
When a parole home plan gets denied, the parole officer assigned to investigate the proposed address submits their findings and the board makes a determination. A denial typically means something about the proposed residence did not meet the requirements, whether that is the location relative to victims or schools, the stability of the household, the presence of other people with criminal records at the address, or a range of other factors the board considers.
Submitting a new home plan means starting the investigation process over with a different address. The parole officer has to visit and assess the new location, submit a new report, and the board has to schedule a review. That cycle does not move quickly under any circumstances, and coming in after a denial means the board is already scrutinizing the case more carefully than it might otherwise.
The practical advice is to make sure the new home plan address is as strong as possible before submitting it. A stable residence with no issues that could trigger another denial, no problematic household members, and ideally someone at that address who can speak to supporting the inmate's reentry. Submitting a second plan that gets denied again resets the clock again and further delays release.
If there is an attorney or parole advocate involved, have them review the new plan before submission to identify any potential red flags before the parole officer does.