I'd get familiar,,very familiar with "Radio Aid Navigation" programme, i bought mine for £79. Mic sim will do but i dont see the need to fly the uppy - downy bit. If you have a good understanding of the navigational aspect of tracking VOR's, NDB,s and flying the airport plates,,,you will be half way there.
The sims are difficult in getting used to at first but when you master the sim and already have a good knowledge of the vor and ndb tracking aspect,,,you wont struggle like i did!
Good Luck!
J