Anyone just wander the waste land picking up experience and add new quests but not touching them at all?

I just hit level 10 on my 3rd charactor and have not completed any quest other than the initial docs house starter.

Has anyone gone further and just scavenged and shot all the way to high levels?

Yup. That's pretty much all I do now. Although I do tend to do some of the companion quests, because part of my 'just running around' includes running around with a few companions (mods). I hardly ever touch the main quest anymore, tho. Only completed the main quest/game twice, in fact. The end just doesn't interest me...it's the getting there that does.

And now even that isn't terribly motivating...I just like the combat, both normal/outlandish/goofy play as well as trying to artificially create extra difficult combat situations for myself.

Yes, but punched and blow my way through the game, I got to level 26 or so killing every NCR camp and danger area.
Then got a bit bored 40+ hours in and finished off the CL quest line.

Now I tend to do it first in the areas around Goodsprings then move onto quests.

Ive actully thought about making a character and kill EVERYTHING i can.No one will survive under my wraith.

Kill everyone level a bit too fast....so I stop and make a less psychotic but similar character...and holding until Lv20ish