I've never approached LR from Ipsut (or any angle
), but I do know the area.
The road from the Carbon River Ranger Station to Ipsut Creek Campground is closed (washed out, not planned to be opened any time soon). Thats 5 miles each way. Depending on the snow conditions, it may, however, be snow-free, and you would be able to bike it. Going in is slightly uphill (about 500' gain in 5 miles). It takes me about an hour on bike, but I'm slow. Going back takes about 15 minutes and is super fun! Oh, and biking with a huge pack on is not fun (AKA painful). Apparently they make trailer things for road bikes, which might work, but there are some bumpy places that might make taking a trailer tricky.
After you get to ipsut creek it is about 9 miles and 5500' elevation gain to a common camp on Curtis Ridge. That's where you meet up from the normal route from White River Campground. That's about as far as I can tell you about. From there you can find info easily I'd assume.
Oh and those guys that skiied it in a day did it before the road was closed. Still awesome though http://www.skisickness.com/Rainier/Liberty/