I am comping from different midi takes, each on a separate midi track, to a new destination midi track, working in the piano roll view.
 
Is there a way, in the track pane of the PRV, to link the selection of active track, show/hide track, and mute track, so that I can switch between tracks with one click rather than 5, as described below?
 
1-hide active track "A",
2-mute active track "A",
3-select track "B" as the active track,
4-show (unhide) track "B",
5-un-mute track "B"

I suggest you just do the work in the Track View, using inline PRVs if necessary. Any particular reason you need to work in the PRV?
 
If you really have to work in the PRV, try keeping the tracks in view, and muting the clip(s) you're not working on. IIRC, S8 already had the 'Hide Muted Clips' option in the PRV.

The reason I am working in PRV is that I often want to let the note(s) played by the left hand ring over while changing the right hand part, or vice versa.

Otherwise track view would probably be the way to go.
 

Check my replies to your other thread if you didn't see them:
 
http://forum.cakewalk.com/FindPost/3378409
 
Based on that, and what you've written here about, I suggest:
 
- Enable Inline PRV mode on the source tracks in the track view (button in the upper right of each track header in S8).
- Focus the target track by clicking in the track header.
- Lasso select notes you want in one of the source tracks (left-click and drag in S8).
- F7 to set the Now time to the beginning of the selection
- Ctrl+C, Enter (or click OK)
- Ctrl+V, Enter (or click OK)