I would definitely recommend getting a rental car - public transport in Townsville is useless, expensive and doesn't run after about 7pm. Taxi is also not a very ideal way to get around.

Don't know much about accommodation in Ayr or Townsville for that matter (I haven't ever needed accommodation here). I have been to a wedding at Seagulls and had b'fast there a few times and it seems nice but I couldn't tell you what it was really like to stay there. It is a couple of blocks away from the Strand. I guess it depends what sort of accommodation you want - whether you want it to be flash, if you want to cook for yourselves, what you want to do here and what time of year you are coming.

Have you thought about Magnetic Island if you are coming for a holiday? If you are wanting to stay to visit with people it is better to be on the mainland, but if you want a break, Maggie Island has some lovely family accommodation, you wouldn't need a hire car over there (or you could just hire a moke). The ferry is about $30 per adult return if you did want to visit the mainland. Just another thought anyway ...

Sorry that probably wasn't much help.