I just put a ratchet strap around the tire when I put on the Trasharoo, it holds it in place while I hook up the straps. Takes 5 mins tops. I don't drive around with mine on 24/7 so UV issues haven't been a problem. I live in California also, and have never had an issue with rodents getting into it and I sure don't want to stink up my vehicle with the smell of garbage. For the price, it does the job. We use a full size garden variety hefty bag in ours, and I leave it outside for a day or so after a trip for any residual odors.
To each their own, it works for me.