Floss Regularly

Okay, so it's half a bike but my 10 year old lad is preparing to unicycle 10 miles in the summer. Somehow I've got to try and keep up with him on mine which may result in me walking a lot!

He's done 5 already around the amazing cyclepath network of Milton Keynes, so I think he'll swallows it up easily!!

Fredo_Adagio

In my experience, the most critical part is to be able to stay on for just a few pedal revolutions. If you can make it down the driveway, you can go any distance.
Can either of you free mount? A more difficult problem may be mounting where there is nothing to hold on to.
Is the route flat? You might want a wheel larger than usual, perhaps 29". Even better might be a geared hub. Of course, you might not want anything larger than 24" if there are hills.
You probably already know all this. If you regularly go for miles, you no doubt have more experience than I do.

Lisa Red

I think riding on one wheel is fantastic

UniChris

Eventually. But typically there's an initial adjustment from the way beginners try to control the wheel between their feet (which is insanely exhausting) to simply sitting on the saddle and pushing ever so lightly on the pedals to keep it rolling. Absent a hill, pushing 20 gear inches is, well, pushing on air.

Ironically for true distance rides, it's then necessary to revert back to that initial inefficient mistake and develop the ability to ride while effectively standing on the (still turning) pedals and hovering off the seat for a half minute to get some relief.

Indeed a concern. Best quick solution would be to arrange a bicycle escort by someone sturdy enough to lend a shoulder. Panniers for water, extra layers, etc could help too - I ride solo centuries with essentially everything but refill water, but it's a lot harder to carry stuff on a unicycle.

Larger wheel, perhaps. Geared hub, no - not only do they cost a fortune but they're very unnerving and take a long time to develop confidence to ride, as a geared up medium wheel doesn't have the stability of a large wheel. Apart from the mounting challenge, and the initially intimidating height, an ordinary direct-drive 36" unicycle is a breeze to ride as everything balance wise happens so much more slowly than on a smaller wheel. But that's probably too big a jump for the asker, vs something like a 26.

Anyway, it sounds like the event happened over the summer, how did it go?