It looks like there is a road from Lugu Lake to Panzhihua, and then a highway to Yuanmou.

Yes, you can take a bus to Yanyuan from the lake (about 3 hours). Next, take a bus to Panzhihua (about 7 hours). Then, take a bus to Yuanmou (about 2 hours). You needn't go back to Lijiang and Dali. Have a nice trip!

Any idea as per the timings of the buses? Are they scheduled to go one after another or I will need to wait for hours to catch the next bus?

The buses to Yuanmou depart from Panzhihua Passenger Transport Center at 9:20 and 14:00, and the fare is CNY 40 or 45.

I heard that the buses from Yanyuan to Panzhihua depart at 7:30 and 8:30, and that there are two or three buses from the lake to Yanyuan, but I have no idea of its exact schedule. Sorry for that!