If you want faster tyres to turn an mtb into a tourer, get 50 mm Schwalbe Big Apples (I don't like the 60 mm variant). They are sturdy enough for most applications (unless you intend to go wildly off road etc), give good grip on bad roads, they are very comfortable, and finally they are surprisingly fast. Narrow tyres on a stiff mtb frame are uncomfortable, handle badly on gravel roads, puncture more easily, and may not be faster in reality (because they cannot cope with bad road surface).
If you want to ride even faster, and can live with their greater fragility, go for Panaracer Pasela 26x1.75. I have them for very light tours, and love them, but not for loaded tours. If you want to rough it more than the Big Apples can handle, the next step would be the ordinary Schwalbe Marathon (not the stiff Marathon Plus).
If your frame has no provision for a rear rack, Old Man Mountain make excellent racks that will almost certainly fit. If a normal rack will fit, my favourite is the Tubus Cargo, or if the budget is very tight the Blackburn EX. A stiff and strong rack is very important. Try limiting your luggage to what will fit into a set of rear paniers only. That saves the expense of a front rack and front panniers, and if you have front suspension fitting front panniers is always a bit of a compromise.
Willem