I got the Wheel Masters Spare Tire Inflation Kit - Under Chassis Mount - Braided Stainless Steel from eTrailer. Less than $60.
Total about 20 min install last weekend.
I get it is easy to get down, drop the tire carrier, and check the air. Iíve had airstreams for more than fifteen years. It is so easy, I have never do it.
I carry a compressor and could just air up the spare if needed. But, that assumes it still holds air.
So, for not much money and a little time, Iíve an easy way to check and fill air in my spare.