I never used Rant, but a lot of people find it usefull.
Another one you may consider is Microsoft Flight Sim. I was really struggling with NDB work and I just love it now because I found it so easy after using FS. You can fly from practically any airport in the world. 95% of the time the navaids are still the same Freq as the ones on your plates so you can do all the approaches. I found it very difficult to hand fly as there is no feel, so you can set the autopilot to heading and altitude hold.You won't improve your manual flying skills but your proceedures should be sharp. This way your doing more than tracking your doing whole procedures and working out decent rates, flying DME arcs etc.
It will never be as good as practicing with a real aircraft or an FNPTII but its something you can use everyday and keep your mind sharp.