There are a number of rail trails in Canada that you can string together for a reasonable tour. The Erie Canal links Buffalo with New York City (almost). In Europe there are both rail trails and a great number of canal tow paths tours including Canal du Midi in the south of France.

As with endevour, you can spend a little or a lot and it usually has little to do with the enjoyment. I started off budgeting $1,000 for a European trip including air. Now I'm up to about twice that, but for a longer period. The less you plan, the more you will pay.