I was away from NY for 305 days, many of which were after my yearly inspection sticker for both the trailer & RAV4 went out-of-date. As usual, when I asked our local DMV before leaving on the trip how to deal with the inspection when I came back to NY, they said the only way to do it was to call them when I was within a few miles of the NY border & they would mail me temporary 10 day inspection stickers.
I explained that I was camping & wouldn't be able to receive mail & got a blank look & shrug. My solution was to get the RAV4 & trailer inspected at the first town I came to after crossing into NY.
That'll likely be our plan as well. I really don't see an alternative short of aborting the whole trip which we won't do.
We faced a similar situation in Rhode Island. The problem was RI insisted on doing a VIN check before issueing a registration. I had given up hope when I realized that one of the forms processed at the US Customs border crossing included a VIN check. I mailed a copy to a family member back in RI, she presented it to the Registry VIN check people, with a little persuasion got a registration, and mailed it to me as I camped in the N. Cascades.
July 2013 Escape 5.0 / 2012 Nissan Frontier
We faced the same situation towing for the first six weeks without a plate. When the plate finally arrived back home, we had someone forward to us at an expected stop and continued on our way. It probably didn't hurt that we didn't drive over the speed limit or break any other laws.
Thanks to the interstate highway system, it is now possible to travel across the country from coast to coast without seeing anything - Charles Kuralt