It would be nice if you could let the Rock know which 3-4 skills you'd like it to learn next, in case you are going to be AFK for an extended time. Queued skills could possibly be canceled or rearranged as long as Rock was not yet working on them.
Glitch Academy might work well for you. Developed by a player - www.glitch.com/forum/genera... This one doesn't require you to have the browser open in order for new skills to start.
If you don't mind the browser being kept open when you are AFK then you can install one of the scripts that other players have written - www.glitch.com/forum/genera...