Don't know about other folks but I did mine.
I used double sided tape and made some small spacers to go behind the radio since it is flat and the area I put it is wedge shaped. The antenna was mounted in the inside corner of the windshield on the passengers side of the dash. Wires were tucked in under the console and around the edge of the dash.
The first picture had a placement that I could use the clip and then the Roady could be removed and put in another vehicle if desired.
Since that is what you want (to be able to move the unit between cars) I would suggest a position like that.
If you plan to move the unit it saves a lot of time if you buy another clip, power supply and antenna.........................
BUT................after spending the money you can add a $ and buy another Roady and just add via the family plan for only another $6.95 a month.