(Except for the winter weather, which can obviously be a significant problem) it's all mental, Eric.
(Well, mostly mental.)
During the Taste of Carolina in October, Peter Dusel said to me, "you guys down here don't know how easy you have it."
I responded, "oh, yes we do. Not all of us were born and raised in the South."
Peter indicated that he had an R-36-continuous, all of which had been done in New York.
I suspect that he may be more able than many to decide at the last moment to do a Permanent when decent weather suddenly appears.
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As I've written before, getting to R-12 was an adventure and a struggle.
However, since then, the rides have just seemed to happen.
I have a couple friends that have made similar comments.
That noted, almost everyone with a long R-series-continuous here in NC has rescued their R-series on the last day of the month.
However, as recently as the end of November, one prominent North Carolina member (who did Endless Mtns, btw), who'd had a very busy family month. decided to let his R-53-continuous-series go -- he just did not fancy spending all night Nov-30 / Dec-01 being cold.
In 2013, he did 4 ACP SR's, and also a "PBP-qualifying" SR (substituting a 1000 and a 1200 for some shorter rides).
So, I guess he proves that maintaining an R-series can be pretty tough.
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Except for avoiding bad weather, one need not travel to do a Permanent.
Any RUSA member can create a Permanent "out their back door" if need be.
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It is also amazing what a difference maintaining an R-series makes when brevet season rolls around.
"
Doc on a Bike" Keith, the new Tidewater, Virginia RBA wrote that several years ago (
click-here for his R-12 story).
I've experienced the same thing.