I did my first 200k on a Worksman cruiser. Not necessarily the recommended starter bike, but you can do a 200k on a LOT of different bikes, right or wrong. Some of the locals use various carbon-fiber race-oriented bikes, some are on tandems, some on recumbents, some on steel frames with fenders, etc. Whatever floats your boat.
My rando bike for several years was a Raleigh Sojourn, which was $800 or $900 new. I did a 300k with rechargeable lights, spent another $700 or so for a hub-generator setup prior to jumping into a 400k, though. I don't think the Sojourn is made anymore, but there's a number of similarly equipped bikes out there.
I'm currently riding a "gravel bike", which works okay. When I did some rides in Colorado, I found I was under-geared there. So if you have a lot of long steep hills, make sure you have the gearing (or the legs!) for them.
__________________
"be careful this rando stuff is addictive and dan's the 'pusher'."