Gary, you never sound like a braggart. And remember the old saying: "It ain't bragging if it's true!"
How else are you going to report accurately on some of those amazing trips you've taken, without stating the plain factual truth? If the description is exciting or interesting, that's not your fault.
So, back to YNP. I am pretty sure there is boondocking in the national forest just west of West Yellowstone -- I saw some rigs back in the trees, not far from town. But what are you going to do if there is a lot of snow on the ground?
The other problem with staying in the West Yellowstone area is that it is far to the other parts of the park. In snowy weather, that could be a long daily drive!