What's the score with ECEs? I can see for instance the 200k Valley of the Rocks next month, and the start is conveniently about 100 km from home... but ECEs aren't mentioned in the COVID update. I'd assume I can ECE it to 300 km, but what about 400, there and back again?
I'd assume not, but that makes it awfully tempting to do a leg by train, which does seem somewhat counterproductive.
The current limits are events up to cumulative distance of ~300Km - thus you could ECE 100Km either end, but not both (or some other split that accumulated to ~300Km)
The 'thinking' (such as it is)
1, is that at present you're not permitted to spend a night away from home (except for specified reasons that don't include audax).
If you take reasonably standard start times and a-bit-less-than-max ride times for a 200 (say 0800-2000) or a 300 (maybe 0600-0000), that's a day ride.
Obviously if you're quick you might be able start a 400 at 0600 and finish before bedtime, or if you're ECEing 100+200+100 you could make a case that 0200-0800-2000-0200 is a day ride, but those aren't exceptions we will make at present.
Depending on how you implement it though, Arabella's suggestion could fall inside both the letter and the spirit of the regulations and the rules ...
(Or, depending on stations and timetables, train-50-200-50-train?)
1: I should admit that I'm part of the 'thinking' ...