You are right Egnaro.
They are two totally separate zones.
The entrances to SolA and SolB are on the south side of the big lava pit and the Temple entrance is on the North. Temple is almost completely quest related. The only slight silliness in there is "Don't Hail the Effriti". It will make you unpopular, not sure why.
SolB is a nice zone but get away from the zone in asap. It is permanently trained. In fact buff up outside and zone in expecting to find a train. Especially if there are beat-up people sitting outside.
The area nearest the zone in has kobolds. These range in difficulty and some are casters. The noble is a charmer - you have been warned. Beyond them you have a couple of caves of sonic bats (no red shoes) and then going deeper the LDCs (Lava Duct Crawlers) and an assortment of fire imps and elementals. Ultimately the Fire Giants although they are not exp mobs as they are on an 8 hour spawn. Beyond them lies the lair of the dragon Lord Nagafen - again not an exp group mob.
Probably more in there as well. There are some decent drops for an old world zone. The Effriti Lord drops
Golden Efreeti Boots.
I used SolB to PL my ranger for a while once Crystal Caverns started going blue. It is fine when empty but the trains make it a bit annoying when you are sharing it.