The Great outdoors

It is damp and grey outside. I have to leave the house in less than half-an-hour for a routine blood appointment and I am trying to fit in all my usual computer based jobs before the day proper starts. The children, inspired by Horrid Henry, want to build a fort. In the garden. In principle I was excited, I was already beginning to think of who I know who might be able to help us, where we could get wood, what a great project this could be and what fun they would have in the Summer. But no, they want to build it now. And they need string, which requires me heading out to the shed to find some. They also need me to release the slide from where it is tied up, literally up, pointing to the sky, off the ground to let the grass seedlings grow, although they never did, so where the slide lands is just a patch of mud. So I've suggested later and now they are building pod-racers out of Lego.
But I wish I was a more out-doorsy sort of mum. In Yorkshire I met another mum who declared that her children were always out of doors. I know that Charlotte Mason praises the virtues of being outside as much as possible. In blogs of other Home Ed families I read of and see the great outdoor adventures they have.
But I hate mud and I don't like being cold. On a balmy Summer's day I love to take a picnic to the park and let the children climb on the fallen trees but I have never liked standing around in playgrounds or woods watching them run about. I would rather be indoors. There are whole days, yesterday being one of them, that we don't set foot outside the house. If I lived in the Big Woods of Wisconsin in the depths of winter then I think this would be ok, but I don't, I live in suburban Outer London and I have playgrounds and parks within easy reach. I fear that I am letting them down, failing to provide something vital, some connection with nature, exercise, fresh air, sunlight.
Perhaps I'll take them to the park later!