Hi Bob,
I made the switch from trailer sailer to keelboat just a couple of years ago. Prior to that, I'd had TS's for about 10 years.
Yes, you'll save on mooring and haul out fees but what you save there you'd probably spend in trailer maintenance and especially in fuel to tow your boat. Yes, you can lower the mast on a TS but depending on the size, weight and stepping/rigging arrangement of the mast, this may not be something you want to do while on the water.
The advantage of them is that you can launch from anywhere there is a decent boat ramp so you can often simply avoid the whole issue of bridges altogether. Also, different waterways are accessible fairly quickly. We once spent the day driving from Sydney to the Gippsland Lakes. Couldn't get there that quickly in a keelboat!
Of course, keelboats have their advantages too which is why I now have one.