What I am about to share won't help with a valve stem issue, but since we are talking "tire pumps".....
Some years back now, I bought a Slime brand compact tire repair kit from Walmart which includes a small 12V tire pump. I bring it along on every trip. It stays in the tow vehicle to support both vehicles in an emergency roadside on-vehicle tire repair. I have never used the kit in any fashion. I really should try the pump and see if it will work well enough to get me out of a pinch. In the case of the motor home, a plug-repair is not something I would consider a permanent solution, but hope would work well enough to address the repair properly at the next practical opportunity.
Here is the Slime tire repair kit. 7-8 years ago, it cost me around $60. I think they are still sold today. I don't endorse it, only because I have never used it. One thing certain, it is very compact and offers me peace-of-mind.

Ron... and all
Those tire repair kits are NOT recommended anymore. In fact, tire places are not permitted to use them anymore.
The only permitted way to repair a tubeless tire by DOT is a patch on the inside. The "plug" style repairs damage the (usually steel) belts in a tire and can cause them to fail, resulting is a true blowout and/or total failure of the tire.
I did not know that DOT does not permit the use of a plug, but I can believe it. If you are not careful, the steel belts can be damaged from the repair.
Where I volunteer, we still use plugs, but there is a real trick about it. If not done right, you can bugger up the tire pretty well. It's all about the screw or nail that made the puncture in the first place. You have to be very careful to pay attention to the angle at which the debris is removed, and insert the plug at that same angle to follow the puncture. You don't want to create a second puncture and questionable steel belts. A nail that gets bent up when forced into the tire, plugging them comes with risk. At the same time, if you saw the tires we patch, you'd say "the tire has bigger problems". We'll patch bald tires most often to buy the owner the time it takes til their next paycheck.
With our PCs, I don't suggest to plug a tire and consider it a done deal. But rather as a substitute for messing with the spare (or if you don't carry a spare). This all of coarse assuming it is a clean puncture and you know what you are doing with the repair process.