Dres itself is quite boring. It have a nice canyon but it is not so interesting that you want to see it again. But Dres's orbit is interesting thing for me. As you have noticed it may give nasty surprises. You must use a real porkchop plotter to calculate orbits and needed dv. Simple dv charts assuming circular orbits on a plane underestimate needed dv. You must also make precise burns and correction maneuvers. Otherwise you notice at Dres that you need 500 m/s more than you calculated. It is fun to do more complicated maneuvers on inclined orbits.