I wouldn't change it.
I've proven to myself, using the best objective means I have at my disposal, that time has little meaning to oil when measured in the kind of intervals we are talking about here. Especially when it's in a vehicle that's stored in a relatively temperature stable storage environment and, when driven, it gets a good long drive. If you were to UOA the oil in your truck, you'd likely find it was perfect.
I have one tractor that soon will finish a three year interval and the oil tested fine at one and two years... we'll see how it does at the end of three when I change it this fall. Take note that this tractor is stored in moderately suboptimal conditions... an unheated horse barn.
I routinely run our pickups and car past a year (18 months or so), now going by miles alone (we put about 5K annually on one pickup and the car and about 1K a year on another pickup, which I will change at 3 yrs). All these have been verified by UOA, by the way, most of them posted in the UOA section. I also have another tractor that's on a two year interval, because it does the tractor equivalent of short hops.
Long time intervals isn't a "universal" recommendation. Poor storage or environmental conditions could dictate a shorter interval. Getting that small annual mileage in short hops, without the benefit of a long run occasionally, might be another. There could be other factors.
As to the oil brand and type, I'm not sure it matters all that much in the realm of one, two or three year intervals. My equipment is using run-o-the-mill dino Rotella and does just great. The PP, or another syn, has better oxidation resistance than a conventional oil, so if you think you need that extra protection, it's hard to argue against a "better" oil. I'd use the oil you like for whatever reason. If I were going to dump it at a 1K/1 yr interval, I'd probably save a few bucks by going to a less expensive oil than PP, but's that's me.
I've not seen any oxidation tests looked at from the storage and not the high temperature aspect. In other words, subject them to similar conditions they would be under inside a stored engine and measure the effects. I know it doesn't seem to show up adversely in my UOAs, and the others in similar circumstances that have been posted, but it would be interesting to carry it to the next level. If anyone knows of such tests, we'd all be grateful to hear about them.
Perhaps the best advice from above is that a truck sitting is not being looked at. In some cases, that may be enough justification to change the oil. If the OP does his own maintenance, the cure is simple: Schedule a periodic "Checkup" followed by a 20-30 mile run (the truck not the owner ( : < ). If it's a shop maintained truck, then could be checked semi-annually by a shop, but expect some pressure to change the oil and techs are often under pressure to find "something wrong" to upsell.
To each their own, but I would rather KNOW I have to change the oil, not FEEL I should. I just have not seen enough objective evidence that oil needs to be changed in the moderate time intervals we are talking about, bearing in mind some caveats. I've proved to myself just the opposite... at least in my own situations.
