Yeah you have a few options:
(*) Flying UA -- This is not exactly what PassPlus Secure was designed for; it's more for if you don't know exactly what dates or routes you need to fly in advance and want to lock in a fixed zone fare. But you could try.
(*) Flying UA -- This is kind of what being UA Gold or higher is for -- book 40 advance-purchase round trips for every weekend as far out as the schedule will allow and if your plans change, use SDC, award flights, or last-minute purchases to supplement your pre-booked schedule. (might be cheaper than using PassPlus)
(*) Flying AS -- Alaska MVP Gold members and higher enjoy waived change fees, a tremendous benefit for a commuter with a semi-rigid schedule.