Yes, I keep the engine and ST 7.5 generator head on the cart full time. The ST 7.5 is over kill but it lives a very easy life at about 50% of it's maximum capacity. On other posts, I've read comments that the STs are most efficient at about 50% capacity (I.e. Perhaps 83% efficient instead of 82% - anyway it never gets too hot).
As for vibration, my engine is well balanced using essentially the Mr X method discussed here on the forum. If done carefully, it works well. All that weight and all that steel helps smooth things out on a well balanced engine. You can view the videos on Rockeyboy911's Youtube page.
As for moving it. I use the winch to allow the until to pull itself onto a 16 foot utility trailer. Easily moved around on the utility trailer, and over to a friend or relatives house in post hurricane recovery operations if needed. In principle, I suppose the winch could also pull the unit up a set of ramps on to the bed of a pickup truck but this would be a dangerous and a tricky thing to pull off. Overall about 2,000 Lbs and still rather top heavy. If you don't have a utility trailer, you might shop Craig's list. Pulling the nursery cart onto a utility trailer and securing the load should be easy. Utility trailers are so very handy for hauling hay, yard cuttings, junk, furniture, trash, etc. and can usually be purchased rather cheap for a single axle.
I hope this was information was helpful.
