Okay, well, I have Boone as a companion, and I was running through the mountains from V.34 to New Vegas. Anywhoo, I decided to drop down the mountain thinking he'd follow, find a path around, which he always has. And I got to New Vegas, and went in. Now, I was fairly sure, as I believe it was in Fallout 3, whenever you entered a new area, your companion would follow you, despite where he was. Anyways, I did some quests in New Vegas (Sadly not continuing the main storyline, as I get the Boone's Hunting Rifle glitch) and I tried to go find Boone. I checked the exact mountain where he would've been, and the surrounding area. I looked for at least an hour, and he wasn't anywhere. I went to Novac, and he wasn't there either. Now, I'm not sure if this a glitch, but I'll leave it here anyways, and any help would be appreciated, and if anyone else has had this problem, then maybe it is a glitch.