If you've done 3 x 200 since xmas, I don't think you need to do anything other than Just Do It.
That's probably more prep than a lot of folks have for an Easter Arrow!
You are in RRTY territory here, for goodness sake!
I'd try to keep up some base miles in the meantime, like perhaps commutes or whatever.
And at the weekends, I'd want to be doing the odd 100k here and there just for fun.
But I'd not get religious about it. Otherwise, nothing special.
Just put the DNF behind you, and get back on the horse.