When arriving in Peru, clients will face an altitude adjustment December 29, 1999 Share 1 -- CUSCO, Peru -- Mountain Travel Sobek's Andean Explorer itinerary spends eight days in Peru -- the shortest and the easiest of its Peru offerings -- and appeals to busy professionals. The itinerary enables them to visit to an exotic destination on an active, walking vacation and return home with just a little over a week out of the office.The operator has scheduled 12 Andean Explorer departures in 2000, one each month. Land cost starts at $2,190 per person, double, which includes hotels, transportation, services of a guide and nearly all meals.For information, contact the firm at (888) 687-6235 or visit the Web site at www.mtsobek.com.Here are some tips for booking clients on walking trips in Peru:Remind clients about the altitude. Although Machu Picchu is comfortable at 7,000 feet, Cusco is at 11,200 feet and takes some getting used to.When I got off the plane from Lima at Cusco, a sharp ache in my right foot flared up (at the place I had broken the foot six years before) and the foot swelled a bit.Mountain Travel Sobek helps ease the adjustment to the attitude by planning a three-night stay in lower-altitude Urubamba Valley for the first nights in the Andes.Remind clients that hats, sunglasses and strong sunscreen are critical when spending time in the sun at this altitude.Despite the precautions taken -- drinking only bottled water and avoiding raw fruits and vegetables -- many in our group came down with stomach aches and diarrhea. Those who brought Imodium were glad they had done so.