I agree with Coopie on this and didn't think I'd see this type advice as I began reading this thread.
There are some good ideas here but you've got to decide what's going to be best for you. As some said you can make money buying rundown homes, remodeling them and then turning a nice profit. But what you have to realize that you will have to put in some of your own time to get things done...whether you do the work yourself or pay someone else to do it.
If I can earn the same or slightly less money in the markets I'd do that. I think you can do better if you work with a proven financial advisor...you'll need to do some homework to find a good person that you trust.
If you diversify your investments there's no reason why you can't make a good amount of return on the money you're talk about investing each year. You can minimize your risk by investing in taxfree municipal bonds, treasuries, etc however you'll give up some return in these investments.
Good luck with whatever you choose......I think you're making a good choice to commit to planning for your future and living debt free.