Nice project, gardening and landscaping may seem painful, but it is I find very therapeutic and when its is all done rewarding, sitting down and casting ones eye over the estate. I did mine last year, put down a whole knew patio , and like you a "dry river bed" I just call it a pebble pathway, also a pond that really was easier than expected to install, it is only "out" by no ore than a 1/4 inch so am happy with its lean!!
Don't whatever you do then rush out and buy a Ninja woodfire outdoor smoker......they are rubbish!!!
RE: Revamping the garden