I learned at the bottom of a staircase. Wedge the tire against the bottom stair to make sure it wouldn’t roll backwards on me, grab on to the staircase’s handrails to assist with the mount, then let go and go for it.
We used ski/hiking poles, portable, use em anywhere, carry em along for mounting assist once you can freeride, ditch em when you don’t need them.
Fencing is a bad idea.
Find a large commercial center, go around back and see if they have a long stretch of clutter free concrete wall. Ride along the wall and “palm it” as you go, switch directions. A slight slope is helpful to keep you rolling.
Excellent UniMyra!
You were at the level when we tell the kids to start going into the abyss (usually thrid grade). For some kids, and me, getting your feet under you and not hitting hard doesn’t seem to come naturally. Other kids are riding into the “abyss” from day one and unicycling far rather quickly.
Some kids have been doing it for months since I started volunteering and still haven’t made it into abyss riding. They still haven’t mastered the smooth peddling needed for unicycling or they are just afraid of falling.
From what I have seen the quick learners are the short fearless ones who also do something like gymnastics or skiing. The ones that take the longest are the tall kids and the ones who are scared of falling. Also ones that seem a little out of shape take longer. My daughter is the tallest in the school - not just her grade - and was scared stiff of falling. So, even with assistance she would freeze the minute she started to fall and hit hard. It took months and she still wouldn’t be riding if I didn’t step in and pressure her to overcome her fear.
In my opinion, you should head to the tennis court to start, but as soon as you feel safe enough you should leave the fence and ride off into the abyss. It took me just over a week before I was riding up the street. As soon as I got the pedal motion down and was convinced I could fall without pain I left this fence behind.
My daughter is learning how to idle now. She still has that fear. Now that she has the motions down, I finally convinced her she can’t learn to idle while holding my hand. I put the overcome your fear pressure on. She tried it, got two idles in, and landed on her feet. Mission accomplished. She will be idling in no time.
I write to much - I should just summarize - 
- Use the fence until you are sure you are not going to get hurt.
- Then ride into the abyss.
Tennis Court
I’ve had good luck helping a few people learn using a tennis court. More specifically, we had success using the corners as a short abyss to jump across. Once they were comfortable pedaling along the fence, I had them cut the corner in increasingly long spans. Knowing they’d be able to grab the fence again momentarily made the abyss less intimidating. After they knew for a fact that they could safely ride several feet, it became easier to pedal off.