Tsomoriri is, in my opinion the most beautiful of all the 3 big lakes in Ladakh. So a trip there well worth the effort, especially if you make it a circular route and come back via the TsoKar lake and Taglang La.
The distance between Leh and Tsomoriri lake (Korzok village) is around 220km and it can be covered on a bicycle in 3-4 days. A major chunk of the route (~150km from Leh to Mahe bridge checkpost) follows the Indus river and road climbs gently (with a few up/down sections ofcourse) from 3300m in Leh to about 4100m at the Mahe bridge. 800m change in elevation over a span of 150km is not much of an issue.
From Mahe bridge the road climbs to the rustic Sumdo village (~25km away), located downstream from the Puga hot springs. From Sumdo the road climbs up to a 5000m pass, goes around the beautiful Tso Kyagar lake and then finally descends down to the Tsomoriri lake. This strech of road from Sumdo to the Tso moriri lake is probably one of the most beautiful streches of road you'll encounter in Ladakh. Especially the grasslands surrounding the Tso Kyagar lake.