I'm actually somewhat interested in this. I'm not so much interested in raiding end game so pushing the limits of what I can solo seems like something that I'd be into.
I'm 59 right now. I did
Crystal Eyes and
Lower Frenzy in Velks while collecting threads for the shawl quest. Both of them aren't too bad and have some nice drops. Crystal Spider Eyes drop off Crystal Eyes and might be an upgrade for some necros.
Been working my way through HS. North is pretty easy, but not a lot of great drops there. Boss in North is an undead necro with a pet, so I'd recommend charming him to make him lose his pet and then let his buddies in the room murder him for you.
I've taken some lumps as I learn my way through West, but I'm starting to get a good feel for it now. Breaking in is the toughest part for me. I haven't gone back to the boss of West yet but have downed the other nameds. Supposedly they are also in north, but (in my limited sample size) I only ever recall seeing
The Spectre Sepulcher in West, who drops the
Adamantite Club which sells for about 4k. Haven't gotten one of those yet though.
I'm hoping to try to solo in South eventually. I'm expecting to get my ass kicked by the summoners, but I have to at least try.
I'd be interested in hearing what else people have done.