Does it have electric actuators? If so, and the boat is out of the water, then a trim tab should be relatively easy as DIY. I would double check that there's power all the way out to it as soon as possible, then order a replacement actuator. (Don't know about hydraulic tabs.)
Two other options are mobile mechanics; this wouldn't need a yard if it's on the trailer; and a boatyard on one of the islands who might have availability (e.g. Philbrook at Roche, Essential Sailing at Friday Harbor, Island Marine at Lopez, etc.)
In any case, I would highly recommend to get replacement parts in advance so they don't have to order and wait on them. Good luck!