I've done ATL to HNL up front direct on the A330, and MEM-LAX-HNL in Coach. I like the chance to walk around in LAX and stretch if riding coach.

Now that DL offers upgrades next month from LAX to HNL I would split the difference. Fly coach through LAX on the way out (with a chance of upgrade), and sleep up front to ATL on the way back.

I just checked a 6 night trip for march 18th. MEM-LAX-HNL-ATL-MEM with the HNL-ATL up front on the A330 was $2200, while MEM-ATL-HNL-ATL-MEM all up front was $3200.

If I didn't want the lie flat coming back I could go through SLC in first both ways for $2k.

Edit - I screwed with the search and was able to get an A fare MEM-SLC-HNL-ATL-MEM for $2200, vs 3200 to go through ATL both ways. Domestic first 767 seats from SLC to HNL and A330 lie flat coming back through ATL isn't a bad way to go.