Do you now run a synthetic or a conventional? Is your Toyota still under warranty? What is your OCI?
If not under warranty of if that is not an issue to you, Mobil 1 10w30 HM is a good choice. It has a heavier base oil(3.66 HTHS) 1000 ZDDP, higher 100C(11.79), a heavier add package, and it is a full synthetic. If you go to the Mobil web site you can compare its pour, pumping, and other stats.
Valvoline full synthetic MaxLife 10w30 has most of the advantages of the Mobil 1 plus it keeps the ZDDP of 800 to meet ILSAC GF-4 cat requirements. They compensate,somewhat, by adding 280 MOLY while Mobil 1 is around 60, or so, MOLY.
If your camper is really heavy, roads uphill both ways, high heat, I would not hesitate to go to Mobil 1 10W-40 HM, but that is just me.