Tried entrance to earth for a few minutes our of curiousity. It's very doable, never came close to dieing... though requires a good amount of chain healing at times. In about 18 minutes, I took out 5 mobs (1 blue exp each), after which I had to stop and med. I had c6 + stealoak though; without it would be a lot more downtime.
If at all possible, avoid the trees... though thats sort of hard since theres one near the zone in in the way. A tree takes "a lot" more healing than the others due to the nasty unresistable snare + DoT it uses. Also avoid dillos. Aside from the fact that they spawn green con adds when they die, they're very resistant and a pain to slow, and also proc a dd that further hinders healing. Looks like this could be an option for exp solo, though it's not partcularly fast, and often theres a group at the zone in.
I've tried Earth solo - in Elemental gear with full raid buffs it's doable, but only barely. (I'm finding Storms and Valor pretty decent low-downtime xp at 70.)
Bloodfields bout the same xp as Storms/Valor ....... and loyalist faction to boot
quite doable. but not worth the time.
also notice the traps spawning nameds thats not soloable