We have used Bass Boat trailers for our boats. We look for 14' trailers in the 1500lb capacity class. You won't need that much weight-carrying ability, but it gets you a better frame. Try to get the biggest wheels you can; the little ones just turn too fast on the freeway! Galvanised frames are worth it if you want to keep the trailer for more than a decade.
Get Bearing Buddies, spring-loaded grease caps for the wheel bearings, and you'll be happier. If you're going to tow your boat long distances, I'd think about a spare wheel and tire. Otherwise a can of flat-fix should suffice.
We make a channel along the center of the frame frome two-by stock to hold the keel. This helps center the boat on the bunks to the sides and helps when loading the boat at the end of the day. The flat bottom could slide on the bunks otherwise when cornering.
These notes apply pretty much to all the boats, but the Vacationer will want a 2000lb capacity trailer at least.