As my experience of exploiting TSMC 0.18um/0.13um ADS RFCMOS PDK, it is very user-friendly. Just do designkit--> install design kits in the main window and everything will be ok. Perhaps one more step to put the model files into designkit-name/circuit/models.
I wish I could have the TSMC ADS 90nm RFCMOS PDK. Could you give it to me? Thanks.