Joshua's grandfather is a prostate cancer survivor so he's inclined to volunteer for challenging fundraising opportunities.
''I like signing up for dumb things and committing myself to things outside of my ability,'' he says.
''I did a triathlon the day before. I'm a terrible swimmer but I just wanted to know what it'd be like to swim in the ocean in front of people.''
The one-wheeled journey took him five and a half hours and the longest stint without stopping was 15 minutes.
''It's exhausting. Every swing on the pedal is less than a step, you'd be quicker walking.
''There's a lot of inclines on the trail. Normally on a bike you'd have a water bottle holder ... it was nearly 30 degrees so I needed to stop to drink water quite a bit. I kind of picked the wrong day to do it.''
Joshua got through the tunnel ''in one go'', which he thought was pretty good.
He received plenty of encouragement along the way and people let him know he was missing a wheel.
''Never gets old,'' he says.
The unicycle is about the fifth one he's owned. Joshua says he forced his parents to buy him one at the age of 15. Being told unicycles were a waste of time, Joshua taught himself to ride in one day.
''It takes patience. It took me about eight hours to learn to bike, it takes most people 6-12 hours. I got it for Christmas and by the end of day I was riding it down the driveway.''
Joshua's main focus is on cycling on two-wheeled bicycles but he's not finished with his unicycle just yet.
''I'm pleased I made it to the end but I walked for longer than I'd hoped for, so it needs to be done again.''