Ladakh's most celebrated trekking route follows a relatively straightforward and scenically glorious route through timeless villages in the roadless Markha Valley before crossing the Kongmaru La (5260m). A plethora of homestays means you don't need to carry much equipment or even food. Having a guide adds to the experience but isn't entirely necessary if you have a good map and a decent sense of direction. Some walkers prefer to join expedition-style groups with horses, tents, a cook and a guide. That makes sense if you plan to extend the trek beyond the main trail.
The standard trek between Chilling and Shang Sumdo (where jeeps wait to whisk you back to Leh) generally takes four or five days. Add a couple more days if starting from Zingchen, for which you'll also need better pre-acclimatisation.