Oil life monitor? I use the dipstick every Saturday and change every 6 months. I guess I’m an old dinosaur but I’ve been doing it for 5 decades and it has worked fine so far.
GM has been installing OLMs for decades, as have most of the auto manufacturers. OLMs have been discussed extensively by automotive engineers in professional societies, and I have no problem using a mature technology to tell me when to change my oil. OTOH, it doesn’t tell me my engine oil level, and I continue to use a dip stick to check that. I guess that is why you mentioned your dip stick.
Toyota uses mileage. My service engine light comes on for an oil change every 10k miles.
Mike; I took my Toyota to the dealer for an oil change and for the first time they looked at the miles driven and the elapsed time and said my next service was Jan. 2017 given the low miles driven. Previously they just added 6 months and put a sticker on the windshield even though by that time thee cat would only nave covered 2500 mules or less.
I.ve always ignored those stickers anyway.
I was only referring to their oil monitor system. It strictly uses mileage. No other calculation.
Mine uses only miles too. Of course mine’s eleven years old! 
In December 1964, after installing a rebuilt motor and transmission in my 1953 Chevrolet, I left my parents’ farm at noon. 50 hours and 2050 miles later, I pulled into Ft. Lewis.
I did pick up a hitchhiker who was a mechanic. He did drive in the daytime, but not much, and I was unable to sleep in the daylight. I did stop each night about 20 minutes. It was below zero and I turned the car off when I did. So, stops were very short. Yeah, I hated my car for a while.
That was before I-80 was done, so parts were on the old highways.
But, I certainly lost my fear of long trips. Now not a spring chicken any more, I do drive short days, but still take 1500 mile trips. I also taught my kids to take long trips.
My daughter lives along the border. Her husband is one of those guys who views a 4 hour trip to San Antonio to be a polar expedition. For her, San Antonio is first gas/restroom stop. After they got married, she told him she wanted to drive to Illinois alone to visit her grandma. He was terrified, but finally relented, and she had a great time.
One thing you can do to help you feel more secure is to ask for the locations of all the GM dealers along the way. The car’s under warranty, so should something happen you’ll know where to tow it. The chances of something happening are extremely slim, but if it helps you sleep better it’ll be nice to have the list.
Drive carefully, take your time, and spend some time visiting the areas you pass through. Don’t go all that way just to say “we passed through some interesting places”.
I still use my window sticker because I am on the 6 month schedule and usually hitting about 3,000 miles. I use my trip 2 mile counter for my 5,000 mile tire rotations.
I always ignore the stickers too. My dealer recommends me to change oil every 3,500 miles while my manual clearly says do every 7,500 miles.