I bought a LoMax kit when they still were available, but you could do the same thing with your stock 205 case. The LoMax cases were machined with all the different bolt patterns in the front of it (you can do this with your case easily). With the new bolt pattern from the 4l60 factory aluminum adapter piece you can mate the two together and it will keep the engine in the factory location. The advanced adapters piece is really long and the factory adapter is a lot shorter so the engine won't move foreward as much.
Here is a link to JB Conversions NP205 page where you can find the pieces you will need like the splined input shaft that should fit the 4l60. Also there is a pic (3rd one at the top) where you can see all the different bolt patterns in the face of the case (this is what you will need to do for the 4l60 adapter to bolt up.
http://www.jbconversions.com/index2.php?pc=3
For the Vss, I machined a flat spot just above the stock speedo cable hole to have a flat surface and drilled and tapped a hole for the vss sensor. I then purchased a metal tone ring from JB Conversions and just made a spacer that fit between the tone ring and the rear output shaft yoke and torqued it all down to spec. The reason I did it this way is because I used the factory gauge cluster and wanted it all to work like the factory system did.
For the shifter I just made up a simple bracket that used the trans-to-transfer case adapter bolts to make it come up through the factory shifter hole. I have a few pics in my build thread of how I did all of this, although I used a 4L80, it's still the same method really.