I may have to move to Essex.
More specifically, I may have to move to within spitting distance of Hockley Woods, because their new parkrun ticks pretty much all of my boxes.
It features trees. It’s undulating enough to be a workout but not so hilly that it’s unrunnable. Underfoot is predominantly well-groomed trail, so it’s forgiving without being evil (though there are, I’ll grant you, one or two mildly muddy sections). The paths are relatively wide, so there aren’t too many pinch points. It’s readily extendible into a longer run. There are two cafes at the end, one cheap, cheerful and outdoors, and the other not-so-cheap, equally cheerful and indoors. Oh yes, and it has free parking (not something I’ll need when I’ve moved to just down the road) and toilets near the start.
It also ticks two boxes that I’d rather it didn’t – it’s net uphill and (just shy of) two laps – but having run some of the other paths in the woods afterwards, if that’s the price of sticking to well-groomed trails and avoiding a muddy-goo-fest, it’s a price that’s worth paying.
If I lived anywhere even vaguely in the vicinity, I’d be adding it to my list of core parkruns. Until then, it will just have to join Cuerden Valley, Hampstead Heath and others in the “fantasy home parkrun” box.
abradypus 
so there is more to Essex than girls dancing around their handbags 🙂 sounds like a great parkrun, how long did it take you to get there?
I refuse to answer that question on the grounds that it will probably lead to questions about my sanity.