A few more, somewhat random thoughts:
Another boat that comes to mind is the Marshall Sanderling -- it's a seaworthy 18 foot catboat with a very spacious cockpit and cabin. Rather pricey though. I have a friend who trailers his up to the Pacific Northwest with us every year for a two week cruise in the Salish Sea. It's a very competent boat both in light and heavy winds. It's not a particularly quick to rig though, but about average. That's not a common boat, but it IS a beautiful sailing catboat. And it's a lot faster than you might expect, compared to a lot of other 18-20 footers.
Head on over to the trailersailor forum. its a sister forum to SBO.
The Main forum is
The Trailer Sailor
There are many brand-specific forums there as well.
I used to take my Potter 19 all over the west coast and to western mountain lakes. Nowadays, I trailer my 24' Corsair trimaran a couple of times per year. This year, as in years past, I've towed it up to the San Juan Islands for a two week cruise, and in a couple of weeks, I'm trailering it to Marina Del Rey and crossing over to Catalina Island for a 4 day weekend. We regularly hit 12 kts of boatspeed in 12 kts of wind. It's pretty small inside, but since it is fast (faster than most 40' monohulls), we can sail to far off destinations. It sleeps 2 adults, sails 4 or more, and drinks 12+.
I keep the Corsair in a slip most of the time, but that costs a couple of thousand dollars per year in slip fees, bottom paint, and diver services. Keeping a boat on the trailer with the mast up, and launching by ramp or crane is a lot less expensive and requires a lot less maintenance. In past years I've kept boats in in dry storage with the mast up and they don't age as fast.
BTW, most of my trailer sailor friends don't have marine heads with pumpouts for daysailing or week long cruises. Many have either PortaPotties or have switched to using "Wag Bags" (or similar products). I personally prefer to take the portable tank out or to dispose of the bag than to find a pump out station. I have switched to using a Restop commode system that's just a bucket with a nice seat and one of their disposable bags. Restop.com or briefrelief.com.
Judy B