So, two things -
1. As far as a dolly goes, I had a PotWheelz and LOVED it! I had the smaller kind, but it still worked really well. It is just like a hand truck, only it holds potted plants. I sold mine after I totally quit moving plants more than a couple of feet around the greenhouse. I suppose if you have a welder, you could turn a hand truck into a pot dolly.
2. I disagree on the dragon fruit. There are some REALLY tasty varieties out there, and you can keep them pruned down. I have three varieties. Get the self-fertile ones, makes it way easier!
A guy here in Nampa Idaho (zone 6/7) is growing them commercially in his backyard greenhouse! As each new variety fruits, he does a little video and rates them. He sells the fruits for $6 each and rooted cuttings for $20 each.
Our Master Gardener group visited his setup. The plants you see in the picture are fruiting size, and some are actually fruiting now. He has four plants, four different varieties in each pot.
You can check out his fruit-tasting videos on Facebook at Treasure Valley Tropical Fruit LLC