I was out for 10 years.
Did some training at local flight school:
Did Instmt ground school, training flights, BFR, IPC, and some sim stuff. A guy who lived near me had a GREAT setup in his basement (he did sim evals for AWAC), and flew with him several times. Also was flying my PC with rudder pedals and a control wheel.
An advantage I had was I was prior military, and had flown a number of large sim hours.
I think, today, that many of the PC sim programs are really, really great, and great for flying instmt procedures. I also did this at the local flight school with instructors.
In case you didn't know, don't bother flying NDBs. I don't think anyone does those in training anymore...
Recently, read about a guy out TWENTY years. He did nothing at all, just showed up day one of class, and had no problems with training.