I went through the same thing with my Precept at first. It is impossible to get to the other stem, which is actually for the outside tire. Invest in the the valve extenders and you'll love the process of checking all your tires, which you should do, prior to any movement of the coach.
I did have mine installed at an RV dealer, but I'm sure a tire place can do it too.
2015 Jayco Precept 31UL
Tow: 2014 Ford Fusion SE HYBRID
Blue Ox BX7420 Avail Towbar
SMI Duo "Stay in Play" Braking
Barley, our Golden Retriever, on board and Buster in spirit!