You can fear kite the two giants at the bottom of Frontier Mountains Giant Fort. Two level 50s on a 6 minute respawn, and they don't agro each other. That can take you to 60 as well.

HS North is fine to fear kite in at the ramp https://www.youtube.com/watch?v=WmDvk3udrhI . SKs have FD if something goes wrong. I haven't died in HS North yet from fear kiting. The trick is just to use your lowest level fear, so the mob doesn't run too far. Also use your pet to pop Harm Touch as much as possible.

Also remember that SKs have summon corpse if the worst happens. But in HS North if you think you are going to die, just die by the wall closest to the North Door on the ramp. You can pull your corpse through the wall if someone opens the door for you.

For solo, Goos/Faire Dragons, HHK, Hole Balcony to 56/57-ish. Then you can do FM giants, Velks (invisible wall area), Geonids in WL.

The trick to soloing to 60 is just being able to start exping quickly after you get on and putting the time in. All of those last 3 are close to port spots, so you can cycle if one is camped and are either safe or easy to get rezed because of foot traffic.

Rats in PoM / Hole are also doable, but a much bigger PITA to get to. Undead at bottom of Hole suffer from the same problem. Also a named will aggro through the wall when it's up.

I was never able to make BW worth my time, but I did try. Found the pulls too long and the pathers too frequent. If you crack it, let us know.

just do velk entrance

mobs are bit beefier but the zem is great, + velious gems and good spot to pick up a duo

There are a bunch of other level 45 guards in BB. You'll likely have to split all the camps with FD (sometimes a lvl 45 comes with a lvl 40 guard social aggroing). Check the wiki for which ones are level 45 (I think most of the guard huts have at least one level 45 guard at them).

On an Enchanter one time I spent a decent amount of time here trying it out as a charm killing cycle and it was pretty solid. It's basically one big circle through BB, stopping to sell at the Druid rings. by the time I got back to the first kill spot it was coming up on the respawn time. There are better places in the game obviously (especially for charm killing) but it's a very safe XPing experience with the ability to farm some decent plat.