I often think I live in one of the best possible locations for cycling, with a bit of everything on my doorstep. There are as many hills around as I could wish for, including some I'd never attempt - the ones that Audax and sportive organisers delight in sending people up! I can easily pick out an interesting and varied ride in any direction with no more than gentle rise and fall, but usually I try to satisfy honour with at least one decent climb. Looking at my list for this year, the most climbing I've done is 7138 ft in 121 miles. The average seems to be about 5000.
As for Eddington, health permitting I should make it to 120 in a few years. At the very outside 121 could be possible, but definitely no more before I run out of time. So any ride of 121 miles plus is all but guaranteed to be Eddington-proof, which is quite liberating.
There's also GPS-Eddington to consider. Only the last 58 centuries are recorded on GPS (Feb 2016 onwards) so my GE-number will steadily climb towards 100. In due course I may come to see this as the more relevant statistic. I think the highest it could ever reach is about 110 (a long way off) so there's no reason to despise rides that don't quite contribute to the next headline E-number.
For a slightly different objective, looking at GPS only I now have at least one ride of every distance between 100 and 130 except 107 and 127. Thereafter it becomes far more sparse - the only other number I have below 150 is 139. Completing the set from 100 to 150 looks to be a reasonable objective, and I'm thinking that for next year's century a month challenge, in the "months of plenty" (March to October) I'll aim for 130+ in each and see where that gets me.