Even though disagreeing ever-so-slightly with Morgan may get me into trouble...
No one has to be a PHRF member (i.e. have a rating) in order to race a sailboat. Since Ericson sold so darned many boats it is easy, in many areas, to race One Design. We have had Ericson 27 classes off and on here, and it would be fairly easy to organize a minimum number (usually 3 to 5 boats) to put together a O.D. class for any local club race. What with all the 25's, 27's, 32's, it is just a matter of getting the word out and doing a whole buncha phone calls.
"Plan B" is to form a level-rating fleet and race boat for boat (scored just like O.D. racing). This has been going on for 25 years in my area. Heck, we have one whole yacht club doing only O.D. and Level Fleet racing...
Some years ago, I formed a fleet myself to have more fun racing my former Niagara 26. I just looked over what was within about 10 seconds a mile of my boat's base rating, called 'em up, and put together a level fleet of about 8 competitors. We had a ball -- we were all very close around the courses with overlaps right and left -- and the positions and finishes were all WYSIWYG.
In general, if you going to race your boat much, I do believe that you should join USS, as this is the governing group for rules and appeals.
Handicapping, whether PHRF, Portsmouth, or whatever, remains a way for disparate sailboats to compete, and afterwards to divy up some trophies. I will do it when no better choise is available, but consider it far down-scale from the "gold standard" that is One Design racing.
Just my .02,
YMMV,
Loren in Portland, OR
(OD racing 5 years, Level Fleet racing for 10, now sailing and wasting bandwidth on the 'net...)
