Depends on your fitness of course.
A few years ago covered a BG in under 19 hrs during July and won 3 shortish races a month later. Having a good kip for 45 mins at my last stop helped my cause I think. And doing bugger all between these events.
BUT ran London Marathon and tried 3 Peaks a week later and totally floundered from Whernside onwards. Did bugger all again and got round the SIPR 4 weeks later. Get fit , rest well.