I've been whittling away on world building a bit too. I'm still building out Home and a few things have happened in simulation: 

* 4000-6000 years after the start of simulation, there is a long, slow gravitational interaction between Home and the inferior planet, Silvernight: 

The result is that Silvernight becomes less eccentric and Home becomes more so. Home's inclination is boosted about 5º:

This wouldn't realistically happen in anything other than a very young system, but I let it stabilize and the setting of the narrative will be about 19900 years after the start of simulation. Thanks to apsidal precession, perihelion is now quite close to northern hemisphere summer solstice. Eccentricity is very high though, and this has the effect of making fairly short (northern hemisphere) summers and long winters. Solar inputs become very low in the northern hemisphere winter, being as far away as it is from the sun-like star (1.15 AU aphelion). 

I had started thinking about a calendar with no real conclusion yet. The seasons are somewhat irregular and there is no moon to provide something like a month:

And here, a fairly loose approximation of surface conditions (not counting sea ice, which isn't computed). It's presently halfway between spring equinox and summer solstice (day 0 on the chart above): 

There is a low technology settlement on the ground at 35º N 75º W (marked with a white dot) which keeps track of the seasons by azimuth of sunrise. 

Still just sketching this out and of course there is a lot to do yet on the climate estimation, but I thought I'd check into TML as I saw the world building thread going on. I'm following the calendar thread with interest.