I always have felt better at high elevations... I read somewhere that Lyme "prefers" mountains and "dislikes" seashores...meaning that it is more likely for the Lyme to cause more troubles at lower elevations and in places near the ocean... I have found this to be true of my own Lyme symptoms...
On the platelets issue, I have intermittant low platelet counts... this may be due to thicker blood (i.e., the platelets are sticking together) or due to the activities of one of the coinfections (Ehrlichia/Anaplasma can cause low platelets, low red blood cell counts, and low white blood cell counts).