Well in case anyone was curious, I thought I'd post an explanation of how I re-installed the Wisconsin WD2-860 engine on my Bolens HT20D. I poked around online and didn't find any other discussion on this. Not saying I did it the right way, but it worked, and I don't think I broke anything.
To set the stage...I bought my HT20D knowing that it had a hole worn in one of the front hydro lines. I couldn't get the line out with the engine in place. It's possible that I could have just raised the engine without removing it completely, but I also needed to fix the PTO lever (turned out the handle just wasn't connected to the rod) and wanted to see if there was anything else that needed attention. The PTO brake needed realigned but that was about it!
When I removed the engine, I removed the bolts securing the dash panel to loosen it, but I didn't remove it completely. I also did not disconnect any hydro lines. I noticed as I hoisted it that the drive shaft end hung up briefly on something, but it came loose before it got serious enough for me to investigate.
To re-install, I tried to re-create the angle at which it came out. But I found that I couldn't make it work. The shroud at the PTO end would hang up on the front engine mounts, or the starter would catch on the engine mount above the treadle pedal, or front of the mounting frame would push against the hydro lines coming out of the valve. My wife and I tried several times to get it to fit through that little obstacle course, but nothing we tried worked.
Today I loosened the steering shaft, disconnected the two hydro lines closest to the engine mounting frame, and pushed the dash column back as far as I could. I dropped the engine in at an angle, letting the shroud on the PTO end rest on the front engine mounts. I worked that as close as I could get it, which was just enough to get the drive shaft mated to the universal joint. Then I put a bottle jack under the engine right behind the front axle, took a strip of plywood, positioned one end of the plywood under the frame cross-piece (the one that holds the lift cylinder) and positioned the other end under the shroud at the PTO end of the engine. I found that by making adjustments in small increments, I was able to sneak around each of the obstacles and get the engine in place. Sometimes I had to hoist or drop the drive shaft end, and sometimes I had to raise or lower the jack. Finally the shroud cleared the front mounts and I was able to drop it right in place.
There might be an easier way to do it, but this worked for me and once I figured it out, it wasn't too difficult. Hopefully this post will help someone else have an easier time with a similar task.