They are all over; all but one required me to be there in person to fill out the forms. It took me days of calling places and asking advice. Not being a resident or having state ID is the problem. Since it's crucial that I start the forwarding order prior to leaving as I only have the 5 days off to travel and new mail will be routed to the new address (usually express), and the mail gets sent when ready - I can't control them. Some is enroute from overseas now; some will go out the week I leave, some on the road and so on. I was just taken aback as I simply never encountered it. I thought perhaps he thought I was planning to exercise domain by "proving" I lived there and wouldn't leave, which is fair. I had our house counsel write a note citing the law saying that I would be in trouble for overstaying as well as reassured him I wouldn't. We agreed that I would only fulfil the first month of the agreement and cancel the second two months. He had a few reviews about being... protective.
The landlord won't budge. I'm OK with the solution, it just ended up being a huge pain and am curious if the USPS has a law (or CA-Tenant law addresses it) in the future in case I run into the problem again. It just surprised me as when I wrote the note I send all owners about a month in advance his reply was almost panicked and said no, absolutely not. I get my mail there; you need to get a PO box. No packages, no mail. Will give you street address apartment number on (date right before I leave) VRBO brokered the arrangement to let me out of the second and third month and did a great job finding me a replacement and absorved a bit of the cost even. But I see why they wouldn't want to get involved; it seems to me this is one of those areas where the peer to peer rental market not being regulated has real issues.
It is an apartment complex with keyed boxes. He will not turn over a key. I'm using a postal store that will give me a street address and accepts packages from all carriers plus is an amazon locker.
Thank you so much for your time and input. I truly appreciate it, especially since there isn't a true issue and it is satisfying a curiosity and helping future hypotheticals.