I thought at first that you meant virtual river cruises down our own UK rivers and I was wondering how that could be achieved, given that most of our own rivers (other than those that pass through industrial areas as they near the sea) are hardly navigable by anything much larger than a rowing boat! However, in the spirit of the OP, I would recommend a cruise down the River Coquet (pronounced coh-ket) which rises in the Cheviot Hills, winding for sixty four kilometres more or less eastwards through the Northumberland National Park and discharging into the North Sea at Amble. Places to visit: Rothbury, NT Cragside House and Gardens, lunch (or stop over) at The Anglers Arms at Weldon Bridge, call on me for a cuppa in nearby Longframlington! ? Stop for tea at The Running Fox here or further down river at Felton, but book a table in advance because they are hugely popular. Nearing the end of your cruise, stop off in Warkworth, where there is a castle, and thence to the fishing village of Amble by the Sea. There is the most beautiful scenery between stops but nothing much else, so it's very restful between your super human efforts with the oars!
Search River Coquet on Google.