Thanks for all the input thus far.
General location is central and west/southwest Ohio. The route isn't "hilly" - 75% of it is on the major rail trail between Columbus and Cincinatti, so there is very very little elevation change there and it is mostly straight, open nice pavement = good to roll fast on (so long as I don't have a head wind). The start and end inevitably will be on roads and there will be some terrain to deal with, but nothing terrible that I haven't already rode.
As far as being able to do a century - yea, no problem there. I haven't done one this season, but I have done 116 miles riding plus a couple miles day hiking in one day before. That was before I converted to SPD clipless pedals/shoes also. With the clipless system my riding strength and endurance is much increased. I still wear out. Where and when is yet to be determined. I haven't hit any periods of "wearing out" on rides this season, but in the past when I got in to the 70-80 mile range my calf muscles would wear out so I would pull my cleats and switch to the platforms with my feet further forward to give my calves a rest. I wasn't as efficient pedaling that way, but I was able to "rest" what was worn out at the same time as making miles as opposed to sitting in one place.
As for gear - I'd be taking my regular trip outing gear plus foul weather gear and stuff for staying over (computer, bath kit, a couple changes of clothes, etc). Regular trip outing gear includes a backpacking stove and folding recliner. I do have a hammock set up (with fly, insulating underquilt, the whole 9 yards - and yes I winter camp in it) but I left it at my cabins. I'm trying to get in touch with someone that might be able to check around for me and mail it home (I'd go get it but it would be a ~2000 mile trip so I'm a bit up a creek there).
Someone mentioned daylight and having shorter days this time of year. You are correct. And with the time change this weekend we loose an hour.
I ran through my ride spreadsheet and looked at the data on times and speed averages. I noticed earlier, also (a bit off topic here) - my Garmin Edge 1000 shows the speed average as a function of the total trip time - which includes stopped time. It doesn't show a "moving average", in other words. I also track some rides on a tablet with GaiaGPS. This shows both a moving average and a total average factoring in "stopped time". So it is interesting to compare. With that information at hand - I figure if I keep a good pace I can probably do the trip in 13 hours including stops. If I run in to any delays or want to rest more then the time could go up from there. So I have in the back of my mind 15 hours. If I work that backwards from sunset that puts me leaving at 3am. That way I am running the dark hours in the first leg of the trip and not the end.