I had a hub/bearing go out on my dual axle trailer 2 years ago. I was VERY grateful to be able to just remove the tire and get home on 3 wheels instead of 4. Not ideal but doable in a pinch.
Ranger Z-20, Yamaha F225.
Yes more expense with a dual axle. More tires, tolls, gas. But... I dragged a single axle 361V all over the northeast for 15 years, now a double axle 487VS (same size as a 519) for 5 years. I will not do a single again. I have had 1 tire blow out, luckily, at low speed. But it was midnight on a very dark night, no street lights, and no breakdown lane. No choice but to put flashers on and hope for best while changing that tire out. I was only 4 miles from home. Double and I would have changed it the next morning in my large driveway with a much better jack, air tools, and significantly less anxiety. I can't imagine losing a tire at 70 with a single axle.
Tandem!
Thanks for the good input. It will be a tandem for sure.