Well I finished a 600K so I can go to PBP now. It kind of felt like "cheating" to do a 600k with only ~1400m of climbing but the wind we had on this ride made up for the lack of hills... the part of Ontario between the bottom of Lake Huron and Lake Erie is flat like a pancake and dotted with windmills, so I should have expected a bit of wind but in a way we got lucky with a strong east wind and ended up with a decent split of headwinds and tailwinds, the best being the last 120km that was 80% tailwinds. I live in an area of rolling hills so it was kind of a nice change of pace for me. I also bought a wider version of my current saddle and switched that out at the overnight stop which seemed to prevent saddle sores from coming back... wish I'd have just done that at the start in hindsight...
Still don't feel excited about PBP though, I haven't done any planning or even booked a flight so I guess I need to get on that.