I'd say 60% of my trips are solo, just me and the truck. Another 30% are me and the wife with the remaining 10% in a small group (never more than 3 vehicles).
My job as an airline pilot requires me to be around people and in loud places. Solo trips to very quiet and remote places are the only antidote I have found to counter the effects of 5 PA systems all blaring at full volume in an airport terminal, the lady who brought her pot belly pig in her carry on because she'd be lonely without him, people who can't find baggage claim in spite of the sign directly in front of them pointing the way in letters 4-feet high, etc, etc. So the independence of going alone, the knowledge that I have pretty much only me and my gear on which to depend, a tough canyon scramble to a thousands of years old archaeological ruin, hearing only the sizzle of a steak on my little Weber Q in camp under a star filled night, asked not a single stupid question for days -- yep, that works for me.
Many travelers and adventurers in the Southwest are familiar with the mystery and legend of Everett Ruess. One of my favorite quotations from Ruess maybe best explains why I like solo travel. “There is a splendid freedom in solitude, and after all, it is for solitude that I go to the mountains and the deserts, not for companionship. In solitude I can bare my soul to the mountains unabashed. I can work, or think, act or recline at my whim, and nothing stands between me and the wild.”
Having said all that, my trip to Expo West includes 2 couples we enjoy very much with a lot of time built in for great conversations in camp set against wonderful backdrops. Just like our rigs are all different in many ways but similar in many others, what we get out of, what we want out of, overlanding is individually different and yet somewhat similar. So are our preferences for going solo and going in groups.