Hello. So we purchased a new Shasta Oasis 25rs in January 2016. The tires are 205 75 14 load range c. Constancy tires. (no doubt made in China) We drove it to Seattle and back to Salt Lake City approx...
I'm a believer in the TPMS systems and you will be too if you tow long enough. Yes, you can get a flat and you will not know it until it's done a lot of damage to your rig.
If you are planning on a TPMS system, steel valve stems are MANDATORY. Others may differ, and even one TPMS mfg told me rubber stems are fine (WRONG!). Do it right the first time and end the discussion.