There is nothing that says you can't do some of both... reach out in advance in forums like this or Adventure Cycling Companions wanted and also see who you meet along the way...

A majority of my riding has been solo but I've also done rides with others. Even those rides with others are in different modes...

In one category are rides with my brother where we are very much linked together. We share camping and cooking gear. This means we're going to travel together every day. We have mostly similar touring speeds so we're also together most of the day. We enjoy each other's company. This has helped in exploring so more distant places (e g. Ukraine/Russia trip for six weeks, Fairbanks to Prudhoe Bay, Guyana/Suriname, Colombia/Ecuador, Timor Lester/Indonesia, etc)

A different category is where I've connected with an otherwise stranger via Internet in advance and then tried traveling together. Some have worked very well but also sometimes end up finding differences in touring speed or touring style and figuring out how to work through them. Two examples:

On my trip across Russia I used Adventure Cycling Companions Wanted forum and received ~15 responses. About 4-5 were more serious and for various reasons it ended up being one person (Mickey) and we traveled together for 4.5 months from St Petersburg to Vladivostok. Some things worked well - shared Dutch language, shared adventures and travel. However also differences: she cycled faster than I did, I had more preference for occasion hotels she more camping all the time, I was more morning person, etc.

So we ended up finding a way to make it work. Most days I left early, she later and would then pass me before stopping ahead somewhere for lunch. We were separate until close to end of the day when we'd sync to find a place to get water and would then camp with tents next to each other.

We also missed each other a few times including once for 10 days in the Ural mountains.

The other example of stranger touring was on trip across the Americas from Prudhoe Bay to Ushuaia. I also put an Adventure Cycling Companions Wanted posting and got more responses. Connected in advance with one person and we arranged to fly into Prudhoe Bay and try traveling together.

We left together but then ended up not traveling together after that. It was a cold day with temperatures in the 20s and light snow. I was faster and we rode together for few miles but it was cold to keep waiting for too long. So we separated and agreed to meet/camp at the first roadside toilet. He never made it and instead camped short by a dozen miles. From that point we kept touch in our respective journeys but ended up traveling separately.

A different category from connecting in advance has been meeting along the way and then riding and/or camping together. I've done this at times on popular routes including Ruta 40 in Argentina, Baja Peninsula and in Australian Outback. It was often informal from camping in same places and then leap frogging. Worked well and figured out different styles and then at some point we went out own ways again.

To bring things back to original point - nothing says you can't do both a "try connecting in advance" AND "meet along the way" approach and see what happens. From my experience I might also expect differences in touring speed and touring styles so unless you know these in advance from prior trips or an existing relationship I suggest keeping things so you can also travel separately if it turns out that works better.
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