If you are looking for a few things to do for your truck, you might want to consider removing the K&N filter and putting something else in it's place. Either a stock filter, or Green filter. K&N just is not a good product for a turbo diesel. They let too much particulate matter through, and that is bad for your turbo, rings, and valves. I know you will be running in a pretty tough environment if you are getting hay from a hay field. You want some good filtration. I would recommend an AirRaid intake and filter. They are a quality product, and they filter just as good as a stock filter, but flow better.
The second thing that every one on here will tell you is that you might want to save your money on the Edge products and get a custom tuned chip from TW (Tony Wildman) or a DP (which stands for ??) chip. They will tailor the tuning to the application, and equipment you have on your truck, and get the best performance from it. Edge (and others like Superchips, Bullydog, etc) are just generic tunes that won't necessarily give you the best tuning for your application. A custom tuned chip will be much better for your transmission (if you have an auto) than any other solution. Bullydog and Edge are known for being hard on your tranny.
I don't know how much the Edge would cost, but the TW my brother got cost him ~$450. He had a Superchip before that, and there was a night and day difference between the two. The neat thing about a TW chip is that you can switch between the 6 tunes on the fly with a knob. With a tuner, you have to reprogram the computer every time you want to change, which take about 10 minutes. Not only does the TW give him more power, and better fuel economy, but the transmission shifts really nice and firm too.
The last thing I will mention is that you will definitely want to get an Exhaust Gas Temperature gauge no matter what tuning option you choose. If you have an automatic transmisson, they you should get a transmission temp gauge too. Boost is a good one as well, ibut it isn't as important as the first two..