Hi Bob,
Looks like you are on you way.
First, about the track, I concur with Harold that you do have two reversing sections. They will have to have an isolated section long enough to hold your longest train. Secondly, feeds to each section of track is not really necessary as long as you solder the rail joiners to the rails. Then you will need drops about every 4 feet.
I don't usually glue rails to the bed, i Spike them as I don't know how many times I have ended up moving things as i went along. then once you are sure that every thing is fine ballast the track. That will definitely hold things in place.
Haven't seen the Rivarossi engine before, but if it is a non DCC ready unit, then you are definitely going to have to isolate the motor from the frame and probably have to run the wires to the tender for the Decoder install.
hope this helps.