It really wouldn't be a "push" to go 7.5K. In your almost ideal circumstances (long drive, warm temps, good oil and filter). 10K is possible. I advise 7.5K immediately with a UOA at the end of it if you need confidence building.
Agree. The best way to optimize the care of your truck is to spend more time and money keeping up its appearance and less time on oil.
I'd say it worthwhile to go to 7K if you can, (which you almost certainly can do). Your time is worth something. If you only drive a little, that's not a big deal, but if you drive a lot, and it sounds like you do, that's significant. One thing that I think that has been established is that pretty much any brand-name synthetic oil is terrific. So If you change yourself, you might as well get whatever synthetic happens to be on sale for nearly the same price as regular. Then you can extend your OCI for another couple of thousand miles at least, I would expect, saving even more time.
So, if it were me, I'd switch to "sale" brand synthetic, test at 8K getting TBN. (Blackstone sells a real handy pump thingy) and assuming its good, run to 10K-11K and test again. Recalibrate from there. If its great you might want to go even further, but if its average, you have your change interval.
You can go nuts paying for these tests, but reassuring yourself that you have a good, conservative, but not absurdly so, change interval is worthwhile, assuming you drive enough to justify it.