The cheapest way to be able to do this is PS elements, it does composties very well for nowhere near the full cost of PS. I use Lighroom for workflow & elements for modification type work. A good pic takes about 1.5 hr or so to get everything cloned in to lok natural. I guess kayak shots are a little easier as the background doesn't change as much (water), maybe 45 min to an hour.
Happy to toss you a copy of elements if you're ever up this way.
Discover Denver, stay there!