GNS430 - wonderful bit of kit! Get familiar with it on the ground. It does magical things, particularly when coupled to the autopilot.
Garmin have a simulator for the PC which I think you can find here
Free 400/500 Series & GNS 480 Simulators
The FAA has some stuff as well on it which you can find here
http://www.faa.gov/training_testing/...0_Syllabus.pdf
There's also bags of stuff on Youtube you can look at.
Some thoughts based on my experiences:
1. Do your downwind checks before you arrive in the circuit and get your speed back and wheels down. It's very embarrassing shunting a 152 up the backside.
2. Do check the wheels and the green light several times (I check on entry to circuit, downwind and final).
3. I think 177's have a mirror on the wing for the front wheel. You might like to see what you could do on the 172 legally.
4. With complex conversion, wheels are the easy bit. I found fiddling with the prop much more challenging.
5. Use the autopilot. I find it's invaluable when I leave the circuit. I put the autopilot on so that I can fiddle with prop and mixture and make ATC calls.
6. Don't use the autopilot...all the time. You should handfly to make sure your skills are maintained.