I want to love Roon Radio like I used to love Spotify.
What was great about Spotify radio was it was five songs ahead. I could remove the weeds. Roon teases the next song, however it is not ‘in the queue’ and it is only one at a time.
If you could show your working and put five greyed out songs at the bottom of the queue it would be amazing, we could ‘thumbs up’ or ‘thumbs down’ them and work ahead
-H
You might want to move this to the Feature Suggestions category (by clicking on the pencil icon in the title and choosing the Feature Suggestions category) and vote for it.
I’m not a big Roon Radio user but I seem to recall that this works? If you thumb a track in the queue it proposes another one to thumb, so you can build a queue in advance. This is also what the help seems to say:
How do I customize my Roon Radio queue?
Once Roon Radio has started, you can head over to the Queue to view upcoming track selections. If you see something you like, give it a thumbs up to add the track to the queue. Clicking thumbs down will skip that track and generate another recommendation, but you don’t have to make any selection if you don’t want to — once the current track has finished the next selection will start playing automatically.
Ah - yes you’re right, it does work that way, so you can quickly build up your queue. Roon just displays one item at a time, rather than five at once.
Back home now and tried it, and in fact it does works like that with repeated 
adding to the queue to build it up.
There’s just one caveat but I don’t think this is what the OP observed: If you happen to choose a seed album that is too obscure to create a working radio, you don’t get any next track suggestion in the queue view, and there is no hint whatsoever for why. You only notice because it just stops after the first track. It should say that it can’t find a track and ideally why.