Unless you have a lot of experiance I would not take a small boat like that out during the really high flows in the winter and spring but other then when the water is really ripping you should be fine. I know people who go out on the Willy all the time in boats like that and do just fine.
As far as the prop goes, well that will be up to you. I run the Salem stretch and I usually destroy one prop per year. Most of the other people who run the same area don't. What is the difference? The driver. I will run to places that other people just write off during low water conditions so that I can fish the spot that I want to and because of that I don't always make it through some of the shallow areas. If you learn the river and all of the shallow prop busting areas and avoid them then you will have no problem with running a prop. If you take chances and run the boat over really shallow areas... well you will eventually get the same results I get.