i'm planning a trek across dartmoor inthe summer and was wondering whether it would be OK to use a bivvy bag rather than a tent? and if so how would i keep all my kit dry whilst i was in the bag- where would my bag and boots etc go?

i was thinking of putting up a small tarp overhead to give myself somewhere to sit if it was raing, somewhere to cook and smewhere to keep my kit.

any suggestions?

thanks

Nathan