Been a while, but I got TW on my IR initial as well. Had done it once before, mainly used WLM.
When I went in I was asked whether I wanted the arc or the backcourse, and if I wanted to hold. You may be asked to hold anyway to make room for a Metro/Dash, no big deal, just more time to sort yourself out!
With regard to entering, dont stress! Just know before you get there at what point you will cross into the CTA at your planned altitude, and work out a fix approavching it. You should be identified by Centre, and they SHOULD hand you off to TW nearing this point, but make sure
you know when you're getting close to the CTA step, so that if you do get forgotten about, you don't punch through without a clearance.
TW tower may ask you to report crossing radials/DME distances, and will sometimes clear you for the next descent upon recieving this call. For example:
TWR: "ABC report passing 15 DME"
<a little later>
You: "ABC at 15 DME"
TWR: "ABC descend to 4000, report passing 10 DME"
(At least, that's what I had, but 1 or 2 radials from Sandon, as I came in via Scone. My descents ended up putting me at the correct height to enter the hold/backcourse)
As has been said, study your Class D radio work, just make sure you know what the differences are. If you've ever done ILSs at WLM during CTAF hours then you probably won't have much trouble with this.
Good luck with the test, don't stress too much about TW, it's pretty easy once you get into it. As has been suggested, if TW tower aren't too busy you can give them a ring, or you can try and pick the brains of a local IFR instructor, and they should fill in the gaps. I should also add, take everything I just said with a grain of salt, it was a couple years ago and it's entirely plausible the procedures or my memory have changed significantly since then!
