Welcome to the forum!
Depending on how mechanically inclined (or adventurous) you are, brakes are not tough to do. As previously stated, hard to stop could be one of several things: Bad booster, cracked vacuum line, dead vacuum pump, bad rear axle seal soaking rear brakes with oil, the list goes on.
Take the time to check things that might be wrong before launching into a fix so you spend time and money actually fixing what is wrong.
With a big truck like that, you might want to consider a hydroboost conversion. I think the system from a 95 Super Duty will bolt right in. Someone else who has done it can correct me if this is wrong.
Enjoy your truck and ask any questions you might have here! There is a lot of experience and it is all free for the asking. This site is also like crack because everyone is so friendly. You can get hooked real easy.