Bryan - I've been touring for 20 years and almost the only time I've ridden with anyone else is when I bump into folks along the way. After my first cross-country trip - solo - lots of my friends talked about wanting to do it, but few made any real commitment. The one person who was most likely starting getting scarce a month before. I knew what that meant.
It takes a lot of planning. Getting your affairs in order, saving up moolah, arranging time off from your job (summer is great for college students), subletting your apartment, having someone look after the pets/kids/significant other - in that order. Unless you really want to do it, you will let one of these things get in the way.
Like a number of folks have said - if you start on the Trans Am, you are almost certain to run into other folks. There's no rule that you have to stick with them either. Two days, a week, or the rest of trip - - most people have different cycling speeds, styles, schedules. By and large, the people I have run into have been great touring companions - and we usually had routes that diverged after a while.
But, I had to shake someone whose entire purpose was staying stoned and hitting bars. I also like to get going early - esp. in the summer - so I get most of my riding done before it gets really hot. Yes, you can jump-frog - but if you are always the one selecting the campsite for the night there can be friction - not to mention waiting to see when your compadre shows up.
Regardless, you can enjoy the company - ride for a few days together - then go your separate ways. White lies are often helpful in this situation and many others when you are solo. Saying, "I just got some bad news and need to be on my own to think about it" works well. If prodded, a firm, "I'd rather not talk about it" should be sufficient for most people. This applies even more for strangers you bump into along the way. If you are uncomfortable in any manner, tell than that you are meeting up with your brother - who just got back from the Middle East - in Bigville down the road.
Many people tour by themselves - on their first tour, too. Of course, it is more difficult for women to do so. I am sorry to have to say that - - but to deny that truth is irresponsible. I look forward to the day when such is no longer the case. Anyhoo, plan away! If someone comes on board for the entire trip - great! Otherwise, just keep on and you will be fine.