A very timely post Greg. I have been frustrated by my lack of ability to retain songs after I have learned to play them. So I just began something new: each of the songs I have already learned are being relearned and once I have them down again, I am going to put them into a rotation of sorts so they see regular play. I don't know of any other way of holding them into my memory.
I can attest to what Christopher says, it really does take lots of repitition until we have muscle memory built in and we aren't thiking so much. Personally I try to hone in on the bass. But I also use the drums to single a change.
And forgot to mention, I need to stay in Performance mode for some time before I can make the jumpt to Jam Along.
Good luck.
This year the diet is definitely gonna stick!